When Does Human Life Begin?
By the embryologists from the moment the spermatozoön joins the nucleus of the ovum until the end of the second week of gestation the product of conception is called the Ovum; from the end of the second week to the end of the fourth week it is the Embryo; from the end of the fourth week to birth it is the Fetus. At what moment during these three stages does the human soul, the substantial form of a man in the full comprehension of the term, enter the product of conception? When does the thing become a human being?
The question is evidently one of the greatest importance. If the rational soul does not enter until the ovum has developed into an embryo, or only after the embryo has passed on into the fetal condition, the destruction of this ovum, by artificial abortion or otherwise, would be a very different act morally from such destruction after the soul had turned the new growth into a living man. If the product of conception has first only a vegetative vital principle, and this is later replaced by a vital principle that is merely sensitive, and this again is finally superseded by a rational vital principle, the destruction by abortion or otherwise of the vegetative or sensitive life would not be a destruction of a rational life. In this hypothesis the killing of the embryo would be a great crime, because the embryo would be in potency for the reception of human life, but the act would not be murder.
The discussion concerning the moment the human soul enters the body is older than Christianity, and it was taken up by many of the early Greek and Latin Fathers of the Church, and revived again and again down to the present day. Plato thought the soul enters at birth; Asclepias, Heraclites, and the Stoics held it is not infused until the time of puberty; Aristotle[15] said the soul is infused in the male fetus about the fortieth day after conception, and into the female fetus about the eightieth day.
Tertullian,[16] Apollinaris, and a few others advocated Traducianism,[17] or a transmission of the spiritual soul by the parents. He said souls are carried over by conception and by the parents, so that the soul of the father is the soul of the son, and from one man comes the whole overflow of souls. St. Augustine used the metaphor, one soul lit from another as flame from flame, without decay in either. Augustine was in doubt as to the origin of the soul, and inclined to traducianism, because it seemed to him better to explain the doctrine of the transmission of original sin. "Tell me," he wrote to St. Jerome in 415,[18] "if souls are created singly for each person born to-day, when do infants sin so that they need remission in the sacrament of Christ, sin in Adam from whom the flesh of sin is propagated?... Since we cannot say that God makes of souls sinners, or punishes the innocent, nor may we hold that souls even of infants which without baptism leave the body are saved, I ask you how that opinion can be defended which thinks that all souls are not made from the single soul of the first man, yet as that soul was one to one man, these are particular to particular individuals."
Again, St. Augustine said:[19] "I do not know how the soul came into my body; he knows who gave it, whether he drew it [traxerit] from my father, or created it new as in the first man." In the Book of Retractions,[20] speaking of the articles he had written against the Academicians before he was a bishop, he says: "As to the origin of the soul, how it is set in the body—whether it is from that one man who first was created ... or, as in his case, is made particularly for each particular individual, I did not then know, and I do not know now." St. Gregory the Great also said he could not tell whether the human soul descends from Adam or is given particularly to each man.
St. Gregory of Nyssa, however, who died about 385, thirty years before St. Augustine wrote the letter to St. Jerome, held that the soul is infused into the body at the moment of conception, and he argues with absolute precision for his opinion.[21] St. Maximus the Theologian, who was martyred in 662, inveighs[22] against the notion that the soul is vegetative at first, then sensitive, and finally intellectual, and he thinks the assertion of Aristotle that the fetus is not animated before the fortieth day is altogether untrue.
St. Anselm, who died in 1109, very dogmatically denied that the fetus is animated at conception,[23] and after his time the doctrine of Aristotle, which is commonly called the Thomistic opinion, became almost general. Vincent of Beauvais, however, a contemporary of St. Thomas, opposed the Thomistic doctrine. Albertus Magnus[24] had the same opinion as St. Thomas, and probably taught it to St. Thomas. In the middle ages all held that each soul is directly created by God, and is infused into the embryo, not at the instant of conception, but when the embryo is sufficiently formed to receive it, which, as Aristotle said, happens at about the fortieth day in males and the eightieth day in females. The Thomists maintained the succession of the three souls; many others opposed this particular opinion.
Thomas Fienus, a physician and a professor in the University of Louvain, in 1620 published a book[25] in which he held that the soul is infused about the third day after conception, and his argument for the early advent of the soul is very sound. As a result of Fienus's revolutionary argument, Florentinus in 1658 brought out a book at Lyons, called De Hominibus Dubiis Baptizandis, in which he held that no matter what the age of the aborted fetus, if it could be differentiated from a mole it should be baptized. This book was brought before the Congregation of the Index. The congregation did not condemn the book, but the author was forbidden to teach that his doctrine holds sub gravi. The book went through many editions and was approved by the faculties of the principal universities and the theologians of the leading religious orders.
Zacchias, chief physician to Innocent X., in 1661 published his Questiones Medico-Legales, and in this he maintained that "the human fetus has not at any time any kind of soul other than a rational, and this is created by God at the first moment of conception, and is then infused."[26] By 1745 the opinion of Zacchias as to the moment life begins was virtually general among physicians, and has since remained the doctrine of physicists. Modern discoveries by biologists have confirmed the fact that human life exists in the impregnated ovum exactly as it does in all stages of life, and no scientist holds any other opinion. There are, however, a few moralists at the present day who incline to the old Thomistic doctrine or to modifications of it.
St. Alphonsus Liguori[27] was a follower of the Thomistic opinion. He affirmed: "They are wrong that say the fetus is animated at the instant of conception, because the fetus certainly is not animated before it is formed, as is proved from Exod. xxi: 22, where in the Septuagint version we find: 'He that strikes a gravid woman and causes abortion, will give life for life if the child was formed; if it was not formed, he will be fined.'" This argument by St. Alphonsus is invalid apart from any facts that may bear upon either the Thomistic or the modern opinion concerning the quickening of the fetus. The text from the Septuagint Exodus is (1) too doubtful in itself to be the basis of any argument; but (2) even if it were authentic just as it stands, the conclusion St. Alphonsus draws from it is not warranted by the premises. The Septuagint text differs from the Vulgate and the Hebrew texts. The Vulgate has it thus: "Si rixati fuerint viri et percusserit quis mulierem praegnantem, et abortum quidem fercerit, sed ipsa vixerit, subjacebit damno quantum maritus mulieris expetierit et arbitri judicaverint; sin autem mors fuerit subsecuta, reddit animam pro anima, oculum pro oculo, dentem pro dente, manum pro manu, pedem pro pede, adustionem pro adustione, vulnus pro vulnere, livorem pro livore."[28] This version has nothing whatever to say about the foetus formatus or non formatus; it is merely an application of the Semitic Lex Talionis, and the form of the law is clearly corrupt and inaccurate.
The passage quoted by St. Alphonsus as that of the Septuagint is not exact even as the Septuagint has it. The full text is: "If two men fight, and one strike a woman that hath [29] in a fine he shall be mulcted; whatsoever the husband layeth upon him he shall give according to decision [i.e., of the judges]. But if it [the babe] be fully formed he will give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe."
This is (1) evidently nothing but an application of the Lex Talionis, with no thought whatever of the biological animation, as such, of the fetus. It means that if a fully formed fetus be aborted, either no real damage is done, as such a child is viable; or the formed child may be maimed, and then the Lex Talionis is to be applied. If the fetus is not fully formed it is not a fit subject of the Lex Talionis since it cannot lose an eye, a tooth, and so on, because it lacks these organs and therefore the law of retaliation is not to be enforced.
(2) Suppose, however, the writer of the text as the Septuagint has it did think with St. Alphonsus that the formed fetus is animated, and the unformed is not animated, even then the conclusion drawn by St. Alphonsus is not warranted by the text. The laws of Exodus do not teach embryology, physiology, or any other part of physical science; and no authority worth a hearing holds that the Scriptures were intended to be infallible treatises on obstetrics or astronomy. Like the other parts of the Bible, the laws of Exodus presuppose the unscientific biological, astronomical, and other physical notions of the time in which they were written—the moral truth is the matter the Scripture is dealing with; there no inaccuracy is to be found. St. John (1:13) speaks of those who believe in Christ's name, "Qui non ex sanguinibus, neque ex voluntate carnis, neque ex voluntate viri, sed ex Deo nati sunt." Here he expresses the contemporary notion, which is also the Thomistic opinion, that men are generated from the specialized blood of their parents. He was interested solely in conveying the truth that those who received Christ were regenerated by him, not through heredity; and he does so, although the biology is inexact. If St. Alphonsus's conclusion is valid as from the text of Exodus, then men are generated ex sanguinibus, and so on indefinitely.
The Massoretic text of this passage seems to be the best preserved: "If men fight, and one hurt a woman who is with child, and her child come forth, yet there is no mischief, he [who struck her] shall be mulcted in a fine; whatsoever the husband of the woman layeth upon him he shall pay according to the judges. But if there be mischief, then he shall give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe." Here the Hebrew text follows the Lex Talionis exactly. If, in a brawl, a man's pregnant wife is struck and abortion results, the offender pays the penalty. If the abortion does not kill or maim the child, the culprit is fined by the Sanhedrim; if the child is killed or maimed, then the penalty is according to the Lex Talionis. In the Hebrew text also there is no mention of a distinction between a foetus formatus and non formatus.
Whether the fetus is animated at conception or some time later, there is no foundation whatever for the notion that the female is quickened later than the male. As was said before, Aristotle held that the human male fetus is animated at the fortieth day, the female at the ninetieth day, and the old moralists accepted his statement. At the fortieth day, however, no one can differentiate sex unless the microscope is used, and this particular use of the microscope is altogether modern—the knowledge requisite for such use was not in existence sixty years ago. At the twentieth day, with the microscope and a stained specimen, a biologist can recognize whether the primordial ova are present or absent and thus determine sex. Only at the eighty-fourth day can sex now be differentiated without the aid of the microscope, but then the embryo must be dissected: nothing can be told from its external appearance. Sex can first be distinguished by the external appearance only at about the one hundred and twelfth day, the end of the fourth month of gestation. Therefore when Aristotle said the male fetus is animated at the fortieth day, and the female at the eightieth or ninetieth day, he was romancing.
The question, then, narrows to this: Is any human fetus animated immediately at conception, or from forty to eighty days after conception? The reason given by the followers of Aristotle for deferring animation is that the vital principle requires organs in the receptive material, but the embryo in the early stages, they say, lacks these organs. This notion, however, as to the lack of organs is altogether erroneous, and the rational soul enters the embryo in the oval stage, immediately after the pronuclei unite: there is organization in that stage of human life sufficient to receive the substantial form or soul. We do not know how long after insemination the pronuclei unite, but the proposition here is that as soon as they unite the human soul enters. Fecundation usually occurs after a menstruation, but not necessarily so; the spermatozoön may live in the tube for seventeen days awaiting the ovum.
The human body is made up of billions of microscopic living cells, all of which are derived by fission and differentiation from the two original single germ-cells, the ovum and the spermatozoön. Some nerve-cells have long processes running along the white fibres through the entire length of the body, but they cannot be differentiated except by the microscope. In the body are also various liquids which are not cellular, as water, saliva, tears, urine, blood and lymph plasma, and the gastric, intestinal, and glandular juices, and these are secreted or excreted by the somatic cells. The cells assimilate nutritive material carried to them by the blood, excrete refuse substances, secrete glandular products, and are the media for all human operations below certain acts of the intellect.
A typical animal cell is commonly spherical in shape, but it may take a great variety of forms through compression. It has a cell-body or protoplasm, which is called also cytoplasm, especially when contrasted with the nuclear karyoplasm, and a nucleus. A few cells, like fat-cells and the human ovum, have an external covering membrane, or cell-wall. There is a part called the Centrosome observable in many cells, and this is made up of one or two minute dots surrounded by a radiating aster called the Attraction-Sphere. The centrosome is concerned in the process of cell-division and in the fertilization of the ovum; it is an important organ in the production of cell from cell, though its full nature and function are not yet known. The Plastid, or Protoplast, is another less important part found in certain cells; and in this by enlargement and differentiation are formed starch, pigment, and in some cases chlorophyl. Vacuoles are seen in cells; and there is an opinion that these may be a special kind of plastid: some vacuoles pulsate.
The Nucleus is the most important part of a cell, the centre of its activity. The specific qualities of organism in origin and development are based upon nuclei, so far as the material element of the living cells is concerned. Vital stimuli pass through the nucleus into the surrounding protoplasm, and these stimuli control metabolism. The nutritive cytoplasm assimilates, but the vital principle energizes this assimilation through the nucleus, for a part of a cell deprived of the nucleus may live for a time, but it cannot repair itself. Constructive metabolism ceases when the nucleus is lost. A toxic disease like diphtheria kills by disintegrating cellular nuclei.
In the nucleus are several elements, the chief among which is Chromatin. Chromatin takes various forms, but commonly it is an irregular network. From the chromatin are derived the Chromosomes in the prophases of indirect cell-division which is the process of cell-division in the human body, except in lymph-cells and white blood-corpuscles, which split directly, or by Amitosis. Indirect cell-division is called Mitosis or Karyokinesis. In the male and female chromosomes, according to a common opinion of biologists, all the elements of parental and phyletic physical heredity are transmitted to the embryo.
Fig. I
A Cell.
Throughout the Cytoplasm is a mesh containing numerous minute granules called Microsomes.
The production of cell from cell is accomplished either by direct splitting of the nucleus and cytoplasm into two new cells, or by indirect division through a series of stages. In a typical direct, or amitotic, division the nucleus is constricted in the middle and divides into two daughter-nuclei. These by amoeboid movements withdraw to the poles of the cell; the cell finally divides between them, and thus two cells are formed. These, again, split into four, the four into eight, and so on. An amoeba by direct division can separate into two distinct new animals in ten minutes.
Heredity here is simple. In unicellular organisms, such as Rhizopoda and Infusoria, each individual grows to a certain stage, and then divides into two parts, which are exactly alike in size and structure, so that it is not possible to decide whether one is older or younger than the other. These organisms reduce the size of their overgrown bodies by division. Each individual of any such unicellular species is a part split off serially from an organism which started into life ages ago. Some of them have come down in uninterrupted life from geological epochs that passed away eons before the first man was created. Many of these unicellular plants and animals have immeasurably the most ancient form of life on earth. Heredity with them depends upon the fact that each offspring is merely half of its parent. In some cases the division has a sexual quality: two cells in Paramecium, and, like Infusoria fuse and then divide if they come into contact; they can, however, split without this sexual process.
Multicellular plants and animals do not reproduce by simple division, and the half of the parental body does not pass over into the progeny. Sexual reproduction is the chief means of multiplication in multicellular organisms, and in no case is it completely wanting; in most it is the only method of reproduction. In multicellular animals the power of reproduction is in the germ-cells, which differ from the somatic cells. Germ-cells do not maintain individual life as the body-cells do, but the germ-cells alone preserve the species. From two of these germ-cells under certain conditions is developed a complete bodily organism of the same species as the parents. These two cells are in a sense the undying cells; the somatic cells die.
Multicellular animals—Man, for example—grow embryologically by Mitosis or Indirect Division. As in Direct Division, typically, the nucleus in mitosis splits first and the cytoplasm secondly; but before the nucleus divides its content undergoes a series of changes. The chromatin loses its reticular arrangement and gives rise to a definite number of separate bodies, usually rod-shaped, known as Chromosomes. In this process the chromatin becomes a convoluted thread, called the Skein or Spireme. The thread thickens and opens out somewhat, and finally breaks transversely to form the chromosomes, which may be rods, straight, curved, ovoid, and sometimes annular. Commonly the nuclear material fades away and leaves the chromosomes in the cell-plasm. (Fig. II, 2 and 3.)
Fig. II
Diagram of Mitosis.
1. Cell with resting Nucleus. 2. Prophase: Chromatin in thickened convoluted threads, beginning of Spindle. 3. Prophase: Chromosomes. 4. Prophase: Spindle in long axis of the Nucleus, Chromosomes dividing. 5. Anaphase: Chromosomes moving toward the Centrosomes. 6. Chromosomes at the poles forming the Diaster, beginning splitting of the Cell-body. 7. Telophase, Daughter-Nuclei returning to resting state. 8. Daughter-Nuclei showing Monaster below. 9. The two new Cells.
It is almost an established fact that each species of animal and plant has a fixed and characteristic number of chromosomes, which regularly recurs in the division of all its cells. In forms arising by sexual production the number is even. The number of chromosomes in the human cell is said to be forty-eight. There are, according to some observers, forty-seven chromosomes in man and forty-eight in woman. There seem to be twice as many chromosomes in white men as in negroes. Wilson gives the number[30] of specific chromosomes for seventy-four animals and plants. Germ-cells as differentiated from the somatic cells have in the perfected cell always half the number of chromosomes found in a somatic cell.
While these changes are going on in the chromatin the Amphiaster forms. This consists of a fibrous spindle-shaped body, the Spindle, at either pole of which is an Aster made up of rays. In the centre of each aster is a Centrosome, and this may have a Centrosphere about it. As the amphiaster grows the centrosomes are grouped in a plane at the equator of the spindle, forming the Equatorial Plate. (Fig. II, No. 4.) The process so far makes up the Prophases of the Mitosis.
In the Metaphases of the Karyokinesis begins the actual division of the cell. Each chromosome splits lengthwise into exactly similar halves, and these, in the Anaphases of the mitosis, drift out to the opposite poles of the spindle to form the daughter-nuclei of the new cells. The daughter-nuclei receive precisely equivalent portions of chromatin from the mother-nucleus, and this is an important fact in mitosis. As the chromosomes go toward the poles the cell-body begins to constrict at the equator.
In the final phases, the Telophases, the cell divides in a plane passing through the equator of the spindle, and each daughter-cell receives half the chromosomes, half the spindle, and one of the asters with its centrosome. A daughter-nucleus is reconstructed in each cell from the chromosomes. The aster commonly disappears and the centrosome persists, usually outside the new nucleus, but sometimes within it. Every phase of mitosis is subject to variation in different kinds of cells, but the outline of the division given here is the fundamental method.
The germ-cells differ from the body-cells in general by containing half the number of chromosomes characteristic of a given animal or plant. If the body-cell has, say, twenty-four chromosomes, the spermatozoön of the animal or plant from which the cells are taken will have twelve chromosomes and the ovum will have twelve. When the nuclei of these two cells unite in fertilization the resulting primordial cell will have the twenty-four chromosomes restored, the specific number for this plant or animal. In oögenesis and spermatogenesis the phases of "Reduction," wherein the ovum and spermatozoön get rid of half the chromosomes during the stages of maturation of these germ-cells, are somewhat similar for both sexes. The process is very complicated, but it is of importance in the theories of inheritance. All the physical characteristics in a human being that come to him from his parents and remoter ancestors are supposed, by the biologists, to reach him through the chromosomes in the nuclei of the single parental germ-cells. The maternal physical heredity is handed on through the chromosomes in the ovum. The fetus in the womb is a parasite, autocentric, feeding at the start from the deutoplasm, or yolk, in the ovum, and later from the supplies brought to it by the maternal blood. The physical material it gets directly from the mother is very probably all in the chromosomes of the fecundated ovum. Some weeks elapse, and the embryo is quite advanced before it begins to draw food from the mother at all. So far as the father is concerned, there is no doubt whatever that every physical and pathological characteristic that can be handed down—and there are many such qualities—must come through the chromosomes of the paternal spermatozoön. Certain physical characteristics are passed on for centuries in a family—the Norseman's body in northeastern Ireland, the skin-pigment in the American negro, and so on indefinitely—and these qualities cannot come down except through the chromosomes. The germ-plasm has come to us from the first man, and it will be passed on to the last person of the race—we are all literally uterine brothers.
In the reduction of the germ-cells, if the primordial cell that finally produces the ovum has, say, four chromosomes, these four chromosomes first split longitudinally and reduce into two tetrads, or two groups of four chromosomes. Outside the nucleus is a spindle toward which the two tetrads move; they pass out of the nucleus and become the equatorial plane of the spindle; each tetrad divides into dyads (pairs of chromosomes), and one pair of these dyads remains in the ovum, while the other pair leaves the ovum entirely and becomes the nucleus of an abortive cell, called the First Polar Body. Later a second polar body forms and carries another dyad (two chromosomes) out of the ovum, leaving only one dyad, or two chromosomes, in the germ-cells; that is, half the number of chromosomes that were in the primordial cell.
The reduction-division in spermatozoa is similar, but the end process leaves four active spermatozoa, whereas in the ovum the final result is one ovum and three practically inert and cast-off polar bodies. The reduction-division in both ovum and spermatozoön is in reality far more complicated than the broad summary given here. In parthenogenetic insects and animals a polar body takes the place of the spermatozoön, and fuses with the egg-nucleus to start mitosis.
In general, the new nuclei in the cells formed by division are not made de novo, but arise from the splitting of the nucleus in the mother-cell. The new nucleus assimilates material, grows to maturity, and divides again into two daughter-nuclei. Whatever be the number of chromosomes that enter a new nucleus as it forms, the same number issues from it in mitosis. Boveri said,[31] "We may identify every chromatic element arising from a resting nucleus with a definite element that enters into the formation of that nucleus, from which the remarkable conclusion follows that in all cells derived in the regular course of division from the fertilized egg, one half of the chromosomes are of strictly paternal origin, the other half of maternal." It is not strictly true to say that the germ-nuclei fuse: they send in two sets of chromosomes that lie side by side, as has been frequently demonstrated since 1892[32] in many of the lower forms of life, and this law almost certainly extends also to man.
The primordial germ-cells appear in the human fetus about the twentieth day and finally mature at puberty. Then an ovum at menstruation breaks out through the surface of the ovary, and is taken by the fimbriae of the Fallopian tube into the lumen of this tube. Fecundation happens near the outer or ovarian end of the Fallopian tube, and the fecundated ovum finally is passed on to fasten on the wall of the uterus. The spermatozoön is a ciliated cell with the power of locomotion, through the movement of the tail of the cell. It can move 0.05 to 0.06 mm., or its own length, in a second. It thus passes up through the uterus and out through the Fallopian tube, against the cilary motion of the tubal cells, until it meets the ovum.
A human ovum is a typical cell, but it has a covering membrane, and a minute quantity of deutoplasm or yolk, which is not alive, and is food for the growing embryo before the embryo begins to draw sustenance through the placenta. The eggs of birds have a large quantity of food stored in the yolk, since their embryos live in the ovum and draw food therefrom during the entire period which corresponds to the time of gestation in mammals. The "white" and the calcareous shell of a hen's egg are adventitious parts, added in the oviduct after the egg leaves the ovary.
The spermatozoön is a complicated organism. The head is partly covered with a thin protoplasmic cap, and it contains the nucleus with the chromatin. In the neck are two centrosomes. The tail is in three parts with an axial filament throughout, which is a bundle of extremely minute fibrils. In the middle part the axial filament is surrounded by an inner sheath; outside this sheath is a spiral filament lying in a clear substance; and outside the spiral filament is a finely granular layer of protoplasm, called the Mitochondria. This organism is a living animal cell, and it can live in an incubator, or in the Fallopian tube for two or three weeks, altogether removed from the living male body that produced it. Sir John Lubbock[33] says he kept a queen ant alive for thirteen years. This ant, which died in 1888, had been fertilized in 1874, and never afterward. She laid fertile eggs for thirteen years; that is, the spermatozoa in her oviduct retained their vitality for thirteen years.
The human spermatozoön is a living cell: it has (1) the requisite structure; (2) the chemical composition of an organic being; (3) a figure in keeping with its species; (4) an origin from a living progenitor; (5) the explicatio naturae; (6) the power of assimilation; (7) the duratio viventium; (8) the power of reproduction; (9) motion and locomotion. As soon as the ovum breaks through the surface of the ovary it has all the qualities of the spermatozoön except locomotion. These two cells are animal cells, not vegetable; just as single-celled protozoa, like Actinophrys, Actinosphaerium, Closterium, Stentor, and the Amoebas are animals, not plants. It is not possible in our present knowledge sharply to differentiate ultimate forms of plants from animals. To say that animals have the qualities of plants plus a sentient vital principle is not enough. It is very doubtful that even the so-called sensitive plants feel, and it is practically certain that many low forms of animal life do not feel—they have no sentient mechanism. Plants have the qualities enumerated above plus the power of drawing nutriment directly from inorganic material, while animals can draw nutriment directly only from organic material; yet some fungi, bacteria for example, will grow and thrive only on organic material, and animals will take up mineral drugs. It is questionable, however, that minerals which thus find a way into animal cells are really assimilated. They excite or irritate these cells into intenser action, and thus cause growth, rather than affect development by direction. The so-called mineral tonics used in medicine act by irritation.
This irritation or stimulation by drugs can in certain very low forms of animal life start mitosis in the unfertilized ovum, and thus build up part, at the least, of a specific embryo parthenogenetically: here probably a polar body takes the place of the spermatozoön. Loeb, by treating the unfertilized egg of Arbacia (a sea-urchin) with magnesium chloride, started mitosis that resulted, it is said, in a perfect Pluteus larva.[34]
The human ovum is about half the size of a period in the type of this page, and two hundred and fifty spermatozoa will fit side by side along the horizontal diameter of the lowercase letter o here. The nuclei of these cells are extremely minute: they must be stained and be observed with a high-power objective on the microscope before they become visible. This small nucleus of the spermatozoön penetrates the covering membrane of the ovum, enlarges, and becomes the male pronucleus. The pronucleus unites permanently with the pronucleus of the ovum, and together they form the Cleavage or Segmentation Nucleus of the fertilized ovum. This new nucleus gives rise by division to the innumerable myriads of nuclei in the growing body. Hence every nucleus of the child apparently contains nuclear material derived from both parents, as has been said.
The two perfected germ-cells before fecundation are in a state of nuclear rest after the numerous mitotic changes that have taken place in the maturation of these cells. When these nuclei unite in the ovum an intense activity at once is set up. Biologists offer very many theories to explain this awakening force. Herbert Spencer, Herting, and others held that protoplasm when perfected tends to pass into a state of stable equilibrium and consequent lessened activity, but fertilization restores it to a labile state. This and similar theories are verbose amplifications of the obvious fact that the cells start to divide and the biologists do not know the cause. The soul, of course, cannot have anything to do with the matter, because you cannot smell a soul. "Senescence and rejuvenescence" is another sonorous explanation that does not explain, used by Minot, Engelmann, and Hansen. Weismann rejects these theories for his own "Fertilization as a Source of Variation." Anyhow, the fertilized cell starts to divide regardless of the biologists. Adult cells may be stimulated to divide by chemical irritation, by mechanical pressure as in the formation of calluses, traumatism, by any agency that brings about an abnormal condition of the body, but this fact does not explain the normal fission of the fecundated ovum.
In about fifteen days from the date of fertilization the ovum passes through the following stages:
1. The ovum, with a full series of mitotic changes of the ordinary somatic type described above, divides, subdivides, and grows within the cell-wall until a rounded mass of cells is formed, which is called the Morula or Blastula—the original cell-wall, of course, stretches to hold these new cells. They are of unequal size, and they divide at unequal rates.
2. An albuminous fluid collects within the morula, and thus the Vesicle or Blastocyst is formed. The blastocyst is called more commonly the Cleavage Cavity or the Segmentation Cavity. As this cavity widens the cells are seen to be arranged in two groups—(a) an enveloping layer, the epiblast, from the outermost plate of which develops later the Trophoblast, or the nourishing and protecting covering of the embryo; (b) an Inner Cell Mass, made up of granular cells, attached to the epiblastic layer at the Embryonic Pole of the Vesicle. These two stages probably take place in the Fallopian tube, and thereafter the embryo is in the cavity of the uterus.
3. In the third stage the Inner Cell-Mass separates into two layers derived from the inner cell-plate of the blastula. The mass flattens and spreads peripherally, until finally it is divided into two layers. The outer is the Ectoderm and the inner is the Endoderm or Hypoblast. The three steps just described have not yet been seen in the human species by any one, but they are inferred very confidently from what is well known of the development in mammals most closely resembling man in physical formation.
4. By the conversion of the one-layered blastula into two layers of cells, the Gastrula stage of the embryo is attained. The Gastrula consists of two layers of cells surrounding a central cavity, which is the Archenteron, or the body-cavity that will hold the intestines. During the past twelve years many specimens of human gastrulas have been observed. The earliest form was that seen in 1908 by Teacher and Boyce.[35] This embryo was 1.95 mm. in length by 0.95 mm. in width, about twice the size of a pin-head. It showed on section the endoderm, the ectoderm, and the beginning mesoderm, enclosed in a spherical mass of trophoblastic cells. The mesoderm is a plate of cells lying between the endodermic and ectodermic plates. When the mesoderm develops into two plates, a cavity, called the Primitive Coelom, appears between the plates. The Coelom becomes the space between the viscera and the body-walls in later development.
From the primary embryonic layers of cells, the ectoderm, the endoderm, and mesoderm, all the parts of the body are built up. From the ectoderm are produced the skin, nails, hair, the epithelium of the sebaceous, sweat, and mammary glands, the epithelium of the mouth and salivary glands, the teeth-enamel, the epithelium of the nasal tract, of the ear, of the front of the eye, and the whole spinal cord and the brain, with their outgrowths.
From the endoderm come the epithelium of the respiratory tract, of most of the digestive tract with the liver and pancreas, the epithelium of the thyroid body, the bladder, and other minor parts.
From the mesoderm are developed bone, dentine, cartilage, lymph, blood, fibrous and alveolar tissues, muscles, all endothelial cells, as of joint-cavities, blood-vessels, the pleura and peritoneum, the spleen, kidneys and ureters, and the reproductive bodies.
The epiblast now with its mesoblastic lining begins to form the Chorion, an embryonic intrauterine appendage; and the endoderm encloses the Archenteron or primitive gut. Before the end of the second week of gestation the heart is indicated as two tubes in the mesoderm, and the blood-vessels begin to be produced in the yolk-sac. About the twelfth day the mouth-pit shows, and the gut-tract is partly separated from the yolk-sac. The medullary plate of the nervous system is laid down about the fourteenth day, and the nasal area is observable. The maternal blood escapes into spaces about the embryo enclosed by masses of embryonic cells, which have not separated from one another, but which are known collectively as Syncytium.
5. With the third week the stage of the embryo, technically so called, begins. During this week the body of the embryo is indicated. There are three layers of cells, already mentioned, the ectoderm, mesoderm, and endoderm, and these lie on the floor of the enveloping Amnion. The amnion is a loose fluid-filled sac (the caul) enveloping the fetus to protect it from jarring. The fluid in it is the "waters" that escape in parturition when the infant breaks through the caul. The archenteron in the third week shows the beginning of a division into two parts: the part that will go to the body proper of the embryo, and the part outside the body of the embryo which will form the yolk-sac, or umbilical vesicle, from which the embryo will draw sustenance until the placental vessels have been formed. The part of the archenteron that remains within the embryo proper begins in this third week to be moulded into the head-cavity. The forepart of the archenteron will later make the alimentary tract from the mouth to the middle of the duodenum, or small intestine beyond the stomach. The other part of the archenteron wall make the Allantois, the hind gut and the bladder. The allantois becomes a part of the fetal umbilical cord after the formation of the placenta.
During this third week the dorsal outline of the embryo is concave; the heart has a single cavity, which will begin to divide during the fourth week; the vitelline blood circulation begins, and the blood-vessels of the visceral arch are laid down. The digestive system is advanced to a gut-tract, which is a straight tube connected with the yolk-sac. The liver evagination is present and the oral pit is a five-sided fossa. The respiratory system is represented by the anlage of the lungs, a longitudinal protrusion of the ventral wall of the esophagus. The genito-urinary system begins as the Wolffian bodies. The mesoderm starts to segment to form the skin, and the neural canal (from which develop the spinal cord and brain) for the nervous system forms. The fourth ventricle of the brain is indicated, and the vesicles of the fore brain, mid brain, and hind brain are recognizable. The ears, nose, and eyes, muscular system, skeleton, and limbs are also beginning to be recognizable. At about the sixteenth or eighteenth day of gestation the various parts of the embryo rapidly differentiate.
In the fourth week all these parts advance. The atrium cavity of the heart begins to divide; the alimentary tract shows the pharynx and esophagus, stomach, and gut; the pancreas starts, the liver diverticulum divides, and the bile-ducts appear. The lung anlage bifurcates and the primitive trachea is seen. The ventral roots of the spinal nerves appear, the interior ear is indicated, and the eye is deeper. The buds of the legs and arms appear about the twenty-first day—by the thirty-second day even the fingers are present. The four heart-cavities are formed, the intestinal canal is nearly closed, the first indications of the liver and kidneys appear. The child now has reached the fetal stage, and its living body is made up of myriads of cells all derived from the original fertilized ovum. The fetus is then one centimetre, or two-fifths of an inch, in length—about the length of the word "fetus" here.
At the end of the second month the fetus is two and a half centimetres long. The ears appear, and the tail-like process at the lower end of the spine disappears. The arms show the three parts, arm, forearm, and hand; and a little later the thigh, leg, and foot are differentiated. The navel begins to close, the liver develops, the abdomen is yet partly open.
At the end of the third lunar month the fetus is seven to nine centimetres long. The intestinal canal is formed and contains bile. The body resembles that of a human being, but the head is proportionately very large. Bony tissue begins to appear.
Fig. III.
The Development of the Fetus.
At the end of the fourth lunar month the fetus is ten to seventeen centimetres long. Some muscles are movable. The heart-beat is strong. Sex is distinguishable externally. The skin is bright red, and so transparent that the blood-vessels are visible through it.
Toward the close of the fifth lunar month the head is about the size of a hen's egg. The skin is somewhat less transparent. There are indications of hair and nails. The eyelids are closed. Parts of the brain and spinal cord are formed. Such a fetus may live for five or ten minutes if removed from the womb, and it may make attempts at respiration.
At the end of the sixth lunar month the fetus, if born, may live for several hours under favorable circumstances. Its respiratory, digestive, and related organs are not developed, and no artificial feeding will keep such a child alive. The brain cortex, the organ of consciousness, begins to laminate into three strata of nerve-cells at the beginning of the sixth month.
Here the time of fetal viability outside the womb may be considered. Langstein, of the Augusta Victoria Hospital in Berlin, reported[36] a study of the growth and nutrition of 250 prematurely born infants, and he found that a weight of 1000 grammes (21⁄5 pounds) and a full body length of 34 centimetres (133⁄5 inches) are the lowest limits for viability under proper circumstances. A fetus 1000 grammes in weight and 34 centimetres in length has completed the sixth solar month, or the sixth and a half lunar month; that is, it is viable at the beginning of its seventh month, servatis servandis.
The child at term, as a rough average, is from 48 to 52 centimetres (19 to 201⁄2 inches) in length, and it weighs from about 63⁄5 to 71⁄2 pounds. It is impossible, however, to obtain the sizes and weights of infants in utero with scientific accuracy, because the date of conception cannot be determined with absolute certainty, and individual fetuses vary as do infants after birth. A full-term infant sometimes may weigh only 31⁄2 pounds when the mother is diseased, and again an eight-month fetus will weigh as much as 8 pounds. Large muscular and fat women have large babies; women of the well-to-do classes have larger babies than do the poor; women who work during gestation bear smaller babies than do those women that rest. Mothers who work in tobacco, lead, or phosphorus have puny babies; white children are larger at birth than negro children; boys at term are 3 to 5 ounces heavier than girls.
Langstein says that prematurely born infants weighing from 900 grammes (311⁄2 ounces) to 1500 grammes (31⁄2 pounds)—that is, all born before the seventh solar month—must be kept in hot-water incubators in a room with ordinary ventilation. Babies weighing 2000 grammes (41⁄2 pounds) or more get along in an ordinary crib if they are kept surrounded with hot-water bags. Such children are to be fed with human milk through a catheter passed into the mouth or they die of inanition. Only a few of them are strong enough to suck from a bottle, and these give up the effort after a few days and die. They cannot utilize fat, even from milk; and all artificial food is dangerous.
Most of the prematurely born become rachitic, and even human milk is not preventive of this condition. Rachitis is a constitutional disease, characterized by impaired nutrition of the bones and changes in their shape. In the third or fourth month craniotabes is frequent—that is, an atrophy of the skull bones with the formation of small conical pits. These infants show also a morbid tendency to convulsions—spasmophilia. Such diseases are caused by a lack of mineral salts, which normally are carried to the fetus by the placental blood during the last two months of gestation. Because of this lack premature infants require the administration of lime salts in their food; they also need iron because they are anemic.
A fetus, then, of six calendar, or solar, months (not lunar) is viable if treated in a hospital by competent physicians. Otherwise it is not viable, except in a strictly technical sense; it will not live more than a few days or weeks. Reports of infants younger than six months as having been successfully reared are not credible—it is easy to make an error in the reckoning.
A full seven-months infant may be reared with proper feeding and skilled care; a six-months infant may be reared (with difficulty) in a hospital with skilled care. If it is certain that the removal of a six-months fetus will here and now save the life of a mother (a very difficult matter to judge by the best diagnosticians), this removal may be done, provided the infant is delivered in circumstances where skilled care, incubator, and proper food are obtainable; otherwise the removal is not justifiable. That the ordinary physician says it is necessary to empty the uterus is not a sufficient reason, as he is likely to act from ill-digested information set forth by professorial pagans, who place no value whatever on human life in an infant.
A most important and essential circumstance in the matter of inducing abortion at the end of the sixth month of gestation to save a mother's life is that in practically every case requiring such interference the diseased condition of the mother has checked the growth of the fetus, and the fetus therefore is really not a six-months child in development. Such an undeveloped fetus is not viable. Eclamptic women, and those who have nephritis, are most likely to have undeveloped fetuses. In cases of this kind the seventh month should be completed before interference.
How is this human body in all its complexity developed from the microscopic germ-cells? There has been a vast deal of ink spilled in striving to solve this mystery, but we come out empty by the same door wherein we went. The early Preformationists guessed that the ovum contains an embryo fully formed in miniature, and development is a mere unfolding of what had already existed. The biologists of to-day mention the Preformationists with superior scorn, and then present Preformationism under other names. Weismann's theory is the most fashionable at present.
In a paper read at the Darwinian Memorial Congress in 1909, Weismann said: "With others I regard the minimal amount of substance which is contained within the nucleus of the germ-cells in the form of rods, bands, or granules, as the germ-substance, or germ-plasm, and I call the individual granules[37] ids. There is always a multiplicity of such ids present in the nucleus, either occurring individually or united in the forms of rods and bands (chromosomes). Each id contains the primary constituents of the whole individual, so that several ids are concerned in the development of a new individual." Actually there are such things as chromosomes, and when these are stained and are under the highest power of the microscope they appear to be granular. These granules Weismann calls ids. Beyond the fact that there are such granules, all else is sheer guessing.
He says further: "In every complex structure thousands of primary constituents must go to make up a single id; these I call determinants, and I mean by this name very small individual particles, far beyond the limit of microscopic visibility, vital units, which feed, grow, and multiply by division. These determinants control the parts of the developing embryo,—in what manner need not here concern us."
There is some truth here. The id is made up of molecules and atoms, ions and electrons, and in some manner, of course, these have to do with the development of the embryo; but as to the manner we have not the slightest knowledge, and just this knowledge is what we need to make the theory anything more dignified than a child's game at guessing. There is a structural differentiation in the unsegmented ovum, with all the embryonal axes foreshadowed in it, but this tells us nothing more than that the egg contains the man in germ.
He goes on: "The determinants differ among themselves; those of a muscle are differently constituted from those of a nerve-cell or a glandular cell, etc., and each determinant is in its turn made up of minute vital units, which I call biophors, or the bearers of life."
That these so-called determinants differ among themselves may be true, if they exist at all, which is just the point to be proved. Giving Greek names to inventions does not turn invention into fact. These supposed determinants, he says, "may vary quantitatively if the elements of which they are composed vary; they ... and their variations may give rise to corresponding variations of the organ, cell, or cell-group which they determine." Professor Dwight said:[38] "This is what is palmed off on us for science!" Weismann assures us we must admit this farrago of clumsy fiction, otherwise we should be forced "to assume the help of a principle of design."[39] In the name of common sense, then, admit a principle of design, and be done with it!
Darwin's Gemmule Theory is the same guessing; and Weismann rejects it because he did not think of it first. As a theory the gemmule plot is just as good and just as bad scientifically as Weismann's. The chief objection to such imagining is that after its authors have put it into print a few times they lose all sense of humor, and mistake phantasms for facts.
Up to the present time we have discovered no living organism lower in grade than the cell. If life ever originated from inorganic matter, it appeared in an organized cell. The Weismann ids, biophors, and the rest, supposing they existed outside his own imagination, are not more capable of independent life than is a chromatin granule. In any event, these biophors could not have originated spontaneously in the first living being; and if they could not so have come into existence, life could never have begun. However primitive any organism is, it must be able to nourish itself and to develop into a higher specific form; but such a variety of functions supposes differentiated structure, composed of unstable chemical substances, a correlation of parts, a purposeful anticipation of ends. Inorganic substances, crystals, and the like are characteristically stable, not unstable; and these could not have been brought into the organic state on an earth burnt to a cinder and devoid of chlorophyl, which itself presupposes organic cells. Whence came also the absolutely essential form of energy, directive of vegetative life? The only possible explanation is that life was created, not evolved by a stranger miracle from a lump of lava.
We know the successive steps in the growth of the embryo from the time of fertilization to the end of gestation, but how this vital process is effected is not so evident. What we are certain of is that there is a vital principle of some kind from the beginning, and this is the matter of real importance in the present discussion. The old moralists held that this principle in the human being is at first vegetative; after a while that vegetative vital principle is expelled by a sensitive principle; and finally this sensitive soul is expelled by the rational vital principle, or human soul. St. Thomas[40] says: "Some tell us the vital acts that appear in the embyro are not from its soul, but from the soul of the mother, or from the primitive force in the semen. Both these statements are false. Vital operations, as sensation, nutrition, growth, cannot come from an extrinsic principle; therefore it must be admitted that a soul preëxisted in the embryo, nutritive at first, then sensitive, and finally intellectual." After showing that an intellectual soul cannot be evolved from lower forms, he concludes: "Therefore we say that since the generation of one thing is always the corruption of another, in man as in other animals, when a more perfect form comes in this supposes the corruption of any precedent form; so, however, that the sequent form has all perfection that was in the destroyed forms, and something in addition: and thus through many generations and corruptions the final substantial form is attained in man and other animals. This is apparent to the senses in animals generated from putrefaction. Therefore the intellectual soul is created by God at the end of human generation, and this soul is both sensitive and nutritive, all precedent forms having been destroyed."
There is no such thing as the generation of any animal or other living being from putrefaction; but that is irrelevant. St. Thomas's argument proves conclusively that if man has first a merely vegetative soul, and secondly a merely sensitive soul, which includes the power of the vegetative soul, and thirdly an intellectual soul, which does the work of all three, that this final intellectual soul is not an evolution of the first two, but a new form that replaces these after they have served their purpose and have been annihilated. It does not even attempt to prove that man really has first a merely vegetative soul, and secondly a sensitive, and lastly an intellectual soul; it supposes all this. It starts out with the erroneous Aristotelian theory and takes it for granted. The reason for this statement is that the rational substantial form requires disposed matter to work upon, and the Thomists suppose (again erroneously) that in the human embryo during the period immediately after conception there is not enough matter to be a receptacle for the rational soul.
The soul according to the Thomists, who use the Aristotelian definition, is the first entelechy of a natural organic body that has life in potency.[41] It is the determination that gives the body its specific and substantial being; the primal actuation of a body or matter, since only in matter is there a distinction between potency for substantial being and substantial actuality. An entelechy is a realization, actuality, full perfection; sight, for example, is the entelechy of the eye. This body is natural, not merely instrumental; it is energized by an immanent principle, not moved by an external force like a tool. The body is also organic; it must have organs, faculties, parts destined to perform definite functions. To say the entelechy has life in potency means that since life, or the operation of the soul, is an immanent act, there must be a receptacle within which it can be immanent, and the soul is the primal actualization of that organic body, which is in potency to produce those immanent actions in which life consists. A body might be in potency while it still has no principle of operation, or, secondly, while it has such a principle but is not using it. In the second condition the human body is in potency for life at the moment of actualization.
A form fixes a thing in its prχοντοσoper species, and the rational soul is such a form for the human body. This substantial form is the completion, perfection, in operability and existence, of the matter that receives it. It is the formal cause of man, not the efficient cause, although it is the efficient cause of subsequent vital operations. An efficient cause makes something numerically different from itself by its own real and physical action; a formal cause and a material cause do not make anything different from themselves numerically, but they intrinsically constitute the effect—they are intrinsic causes.
The human soul as the substantial form virtually contains vegetative and sensory faculties, and through these lower organic capacities it informs and animates the body. That form, together with the matter, the body, does the vital acts of the composite human nature. The rational soul enters the body at the beginning, and first uses its vegetative faculty until the fetus is far enough advanced to be a subject for the action of the sensory faculty of the soul. Later, some time after the birth of the child, when the body is sufficiently formed, the intellectual faculty comes into use.
The nature of a vital principle is that in which it normally issues. If it issues as a rational substantial form, as in man, it was rational from the beginning. If it was not rational from the beginning, a rational principle replaced a sensory vital principle, and that sensory vital principle replaced a vegetative vital principle. The only reason for these replacements would be that the early human embryo, as has been said, lacks organization sufficient to sustain a form higher than a vegetative principle. If this were sufficient reason for deferring the advent of the rational soul, then a baby six months after birth would have no rational soul because it certainly lacks the supposedly requisite organs. However, as the rational soul is whole in each part of the adult body in the totality of its essence and perfection, but not in the totality of its virtue, because certain organs are lacking in particular parts of the body, it is in the embryo whole in the totality of its essence and perfection, but not in its virtue because certain organs are not yet formed, and it is thus from the moment of conception.
As to the soul itself, Kant held that the soul is not a real, but only a logical substance. The Pantheists, Transcendentalists, and Neo-Hegelians try to identify the soul with the divine consciousness. The Associationists (Hume, Davis, Höffding, Sully) say that the soul is a mere group of sensations. The Agnostics and Positivists (Locke, Herbert Spencer, James, Comte) write volume after volume on the soul to prove that they know nothing about it. Then the Materialists assert that there is no soul of any kind; that we secrete thought as a mule secretes sweat. Yet the vital operations of man are inexplicable as resultants of the physical and chemical properties of matter. There is an intrinsic energy that unifies the actions of man, directs processes, controls the tendency of organic matter to pass into the fixity of the inorganic, and effects metabolism. This intrinsic energy is the entelechy, substantial form, or what is popularly called the soul.
In any organic body there is a formal principle. We know that there are activities that proceed from organic bodies, and a formal principle of such activity is a substantial entity whence the organism derives basically its own kind of action, which determines and orders the activity. There are acts of perception in animals such that an external object becomes so internal to the organism of these animals that it is known by one expressed and immanent image, not only as something objectively existing but as good or hurtful to the perceiving animal. The innate and elicited appetites by which the animal tends toward or away from the object are recognized, as are the spontaneous motions which are directed by that knowledge. There must be a principle whence these actions proceed, and this is either an accident of matter or something substantial. It is not an accident of matter, because action can never arise from an accident; it must proceed from a substance. If you say this principle whence these actions arise is not an accident of matter, but matter itself, you would have an extended, composite, inert mass acting; but even if such thing could act, it could never effect a simple immanent image of an object or group of objects external to itself.
No mere machine can build up itself, can make any remote approach to metabolism as an organized body can; and the principle of this immanent action is not matter itself, because it uses, makes, subordinates matter to itself. That principle is positively one, not one by continuity as matter is. Matter as in a crystal grows by mere aggregation, an organism grows by assimilation; a crystal loses force in formation and growth, an organism accumulates force.
The theory that denies the existence of this formal principle does not explain the phenomena of life in organic beings. Uniformity of tendency toward an end is not a characteristic of mere matter; neither is a harmonious interaction of parts, nor the dependence of parts on the unit, nor motion, nor the reproduction of the species.
Moreover, most of the greatest physical scientists strongly maintain that there must be a formal substantial principle in all living things. Among these are Wallace, Nägeli, Askenasy, Preyer, Fechner, Agassiz, von Baer, E. de Beaumont, Blanchard, A. Braun, Brongniart, Bronn, Burmeister, Delff, Milne-Edwardes, Flourens, Goeppert, Griesbach, Heer, Koelliker, Mivart, Quatrefages, Quenstedt, Spiers, Volger, R. Wagner, Liebig, and Joseph Hyrtl.
The formal principle which coexists with matter in the organic body is really though not perfectly distinguished from matter. A formal principle which is necessary for sensation should be either perfectly simple, or at the least so one that its parts together make up one essence: matter, however, cannot have such unity, and as a consequence the formal principle must be distinct from matter. Anything is like its operation, and the parts of any sensitive activity always result in an activity that is essentially one. If we touch a table, by that single touch we at once know that the object is one, wooden, hard, angular, smooth, extended, and so on, and we also know that one subject perceives all these varied qualities. One eye can convey knowledge at once of a thousand objects miles apart, and these objects can be brought into one perception only by a simple subject. An extended complex subject like matter would get one impression (if it could perceive any impression) on one side, one on another, and so on, but it could not unite these.
The formal principle which is in organic bodies is a true substantial form, actuating the body both as to its nature and substance. Together with the body, this principle makes a being one in itself, such that the matter and the form separably are incomplete as regards operation and being. Now, a form is that principle through which anything is established in its own species; light, for example, is the form of a luminous body, heat of a hot substance. A body, however, is established in the human species by receiving a rational soul, and this soul, then, is its form. It is also a substantial form because the soul itself is a substance, not an accident dependent upon another subject. Moreover, from its union with the body another substance—man—arises, and not a thing added to a substance. Man's body is alive, therefore it is a living substance; but life in its secondary actuality is an operation; in its primary actuality it is an essence. The body is made a living substance, not from itself, but from the soul which is added to it. When the soul departs the body is no longer alive. Now, a principle which by a communication of itself determines the body in its essence and differentiates it as a living substance from everything else, is a substantial form. A substantial form, then, or a soul, exists.
The soul, however, must have disposed matter for most of its operations; it cannot exist as a substantial form bombinans in vacuo; but it does not need a human organism complete in all its parts as a necessary condition for its indwelling. There is organized matter enough in the first cell that comes into existence after the fusion of the germ-nuclei to hold this rational form, or soul, as perfectly as it needs to be held in this first stage of human life.
To inform the embryo any principle, whether it is the rational soul or a force derived from the parental organism, must have organs; and if organs are present, then the embryo is fit to receive the human soul, as the only objection to its presence is a supposed lack of organs. To use other principles when the human soul itself could be present would be a multiplicatio entium sine necessitate, which is a condition repugnant to the universal method of the Creator.
It has been said that the vital activity in the fertilized ovum does not proceed from the rational soul because, "in the first place, it results from the fusion of two vital activities, neither of which is rational; secondly, it results in the formation, by fission, and differentiation, of two distinct and separate living cells, each containing within itself a principle of vital activity. Now this principle of vital activity cannot be a rational soul, for each cell has its own principle of activity, and in man there is but one soul."
In the first place, that vital activity does not result from the fusion of two vital activities neither of which is rational. It results after the nuclei come together, by particular creation, and replaces their activity—the generation of the last vital force is the corruption of the first that existed in the separate nuclei, not a derivative of that first force. Again, when the embryo is in the two, four, eight cell stage, and so on, there are not two, four, eight vital principles present, but one. Substantial unity is essential to life of any kind, no matter how low its grade; and if each cell had an independent vital principle, any form of resultant life in the mass would be impossible. An aggregation has no unity of substance; there would be as many substances or natures as there are individual beings in the aggregate, no matter whether ordered or in a mob, consequently no life at all as a life.
The embryo in the two-cell stage is not made up of two independent organisms, any more than the right and left halves of an adult man are two independent organisms. The cells in the two-cell stage of the embryo are the right and left halves of the body, not two individuals, as has been proved repeatedly by biologists. Roux[42] punctured with a hot needle one of the cells in the two-cell stage of a frog embryo without killing the embryo, and it grew into a half-frog larva. Analogous results were obtained by operating in the four-cell stage. Later, Pflüger, Schultze, Enders, and Morgan corroborated the work of Roux. Newport[43] discovered this fact sixty years ago.
In analyzing the structure and functions of the individual cell we regard it as an independent elementary organic unit, but this view is solely a matter of convenience, almost a convention. All the billions of cell's in an adult man are inseparable parts of the single living person. No cell exists as an independent organism in multicellular animals, except the germ-cells, and these only after separation from the gland of origin. Indeed, the biological theory of heredity, already mentioned here, wherein the germ-cell is supposed to carry forward the entire heredity, is now changing toward the view which makes all the somatic cells influence the germ-cells; that is, the body-mass of cells sends on heredity through the germ-cell as the instrument. Adult organisms do not make cells de novo. New cells are formed by division from preëxisting cells, but some biologists think the body-cells so affect the new germ-cells as to influence heredity.
The cells are organs, nodal points, of a single formative power which pervades the mass of cells as a whole. The protoplasm of each cell is not only in direct apposition with its neighbors, but nearly all biologists are now inclining to the opinion, which Heitzmann proposed in 1873, that division of cell from cell is incomplete in nearly all forms of tissue; and that even where cell-walls are present (an exceptional condition in mammals) they are traversed by strands of protoplasm, by means of which the cells are in organic continuity. The whole body, he contended, is thus a syncytium (a mass of continuous protoplasm stippled with nuclei), with the cells as mere nodal points in an almost homogeneous protoplasmic mass. There are cell-bridges between the sieve-tubes of plants. In 1879 Tangl discovered such connection between the endosperm cells of plants, and later Gardiner, Kienitz-Gerloff, A. Meyer, and many others demonstrated that in nearly all plant tissues the cell-walls are connected by intracellular bridges. Ranvier, Bizzozero, Retzius, Fleming, Pfitzner, and many other observers have found these protoplasmic bridges in animal epithelium. In the skin of a larval salamander they are quite conspicuous. They are known to occur also in smooth muscle-fibre, in cartilage cells, in connective-tissue cells, and in some nerve-cells. Harrison found, in 1908, that in frogs the nerve-fibres develop out of these intracellular bridges. Dendy in 1888, Retzius in 1889, and Palladino in 1890 have shown that the follicle cells of the ovary are connected by protoplasmic bridges, not only with one another, but also with the ovum; and similar connection between somatic cells and germ-cells has been found in a number of plants. Thus even the germ-cell is not independent until it has actually broken away from the gland. A. Meyer holds that both the plant and animal individual are continuous masses of protoplasm, in which the cytoplasmic substance forms a morphological unit, no matter what the cell is. That opinion is not finally settled as regards the animal after the fetal stage, but it is much stronger as regards embryos. In the early stages of many arthropods it is certain that the whole embryo is at first an unmistakable syncytium. This is almost established also for Amphioxus, the Echinoderm Volvox, and other animals. Adam Sedgwick holds that it is true for vertebrates up to a late embryonic stage. Mitosis, then, is a form of growth of a mass, not a generation of new individuals.
Whether chromatin or any other element in the germ-cell be the idioplasm in which heredity inheres, differentiation is a progressive transformation, through physical and chemical changes, of the substance of the ovum, and this transformation occurs in a definite order and a definite distribution in the ovum. The changes result in a cleavage of the egg into cells, the boundaries of which sharply mark the areas of differentiation. These cells take on specific characters. In the four-celled stage of an annelid egg these four cells contribute equally to the formation of the alimentary canal and the cephalic nervous system, but only one of them, the left-hand posterior cell, gives rise to the nervous system of the trunk and to the muscles, connective tissues, and germ-cells. The relation between the four original cells, or blastomeres, and the adult parts arising from them, is not fixed, because in some eggs these relations may be artificially changed. A portion of the egg which normally would develop into a fragment of the body will, if split off from the others, give rise to an entire body of a diminished size.
Conklin says[44] that in the ascidian Styela "there are four or five substances in the egg which differ in color, so that their distribution to different regions of the egg and to different cleavage cells may be easily followed, and even photographed, while in the living condition. The peripheral layer of protoplasm is yellow and it gathers at the lower pole of the egg, where the sperm enters, forming a yellow cap. This yellow substance then moves, following the sperm nucleus, up to the equator of the egg on the posterior side, and there forms a yellow crescent extending around the posterior side of the egg. On the anterior side of the egg a gray crescent is formed in a somewhat similar manner, and at the lower pole between these two crescents is a slate-blue substance, while at the upper pole is an area of colorless protoplasm. The yellow crescent goes into cleavage cells which become muscle and mesoderm, the gray crescent into cells which become nervous system and notochord, the slate-blue substance into endoderm cells, and the colorless substance into ectoderm cells. Thus within a few minutes after the fertilization of the egg, and before or immediately after the first cleavage, the anterior and posterior, dorsal and ventral, right and left poles are clearly distinguishable, and the substances which will give rise to ectoderm, endoderm, mesoderm, muscles, notochord, and nervous system are plainly visible in their characteristic positions." Conklin followed these cells in every division until the embryo was developed, making a complete genealogy up to the ovum proper.
De Vries[45] assumed that the character of each cell is determined by "Pangens" that migrate from the nucleus into the protoplasm. Driesch and Oscar Hertwig held that the peculiar development of a given blastomere is a result of its relation to the remainder of the cell-mass, an outcome of the action upon it by the whole system of cells of which it is a part. Hertwig said:[46] "Each of the first two blastomeres contains the formative and differentiating forces not simply for the production of a half-body, but for the entire organism; the left blastomere develops into the left half of the body only because it is placed in relation to a right blastomere." Wilson[47] and Driesch[48] came to the same conclusion about the time Hertwig wrote. Driesch said:[49] "The relative position of a blastomere in the whole determines in general what develops from it; if its position be changed it gives rise to something different; in other words, its prospective value is a function of its position."
A discussion of this matter will be found in Wilson,[50] but the many experiments made in the study of this subject show conclusively that the cells, singly, grouped, and in mass, are a morphological unit, not an aggregation of distinct individuals. They are not, of course, absolutely homogeneous, because such a body could not have organs. The substantial form, therefore, is not confined to the first cell.
The cell-mass, then, has a unity sufficient to be the receptacle of a human vital principle; again, the basic vital operation of the human body at any age is metabolism, and this is actually carried on in the first somatic cell of the embryo as in the cells of the adult man. In the development of the human body in the embryonal stage the energy of cell-division is most intense in the early cleavage stage, and this diminishes as the limit of growth approaches because further division is not needed. When that limit is attained a more or less definite equilibrium is established. Some of the cells in the fully formed body cease to divide, the nerve-cells, for example; others divide under special conditions, as the blood-cells, the connective-tissue cells, gland-cells, epithelial and muscle cells; others continue to divide throughout life and thus replace worn-out cells of the same tissue, as the Malpighian layer of the skin. Cells grow, divide, function, reproduce themselves, and so on, all through their vital activity, sustained by the material brought to them by the blood. Weismann[51] and other biologists think that the vital processes of the higher animals are accompanied by a renewal of the morphological elements in most tissues. The material is carried to the fetus in the womb by various agents, but mostly by the maternal blood after the embryo uses up the yolk; and when the fetal circulation has been established the nutritive material is taken from the maternal blood into the fetal circulation through the placenta, and then carried to the cells by the fetal circulation itself. After the child has been born the stomach and intestines take in the food. The stomach does very little with it except in a preparatory manner; the intestines further prepare it, pass it into the body, where it is again modified by other organs, and finally it is carried by the blood to the cells. The cells really use it; the other organs are the farmers, grocers, railways, and the like; the cells are the consumers. So far as the essential processes are concerned, the embryological cells act as do the adult cells.
The first cell has contractility, protoplasmic motion; it can absorb perfectly all food-stuffs necessary for it from the deutoplasm of the ovum, and the water that passes in from without to the ovum. In a few days the embryonic cells have used up the deutoplasm and are taking up food from the maternal blood as perfectly as any adult cell does, and are exercising their function of building up and sustaining whatever part of the body they are destined for; and this with all the complicated metabolism of the adult cell. Cell metabolism is the fundamental, chief, organic act of any human body at any age. That the embryo does this impelled by the virtus formativa transmitted from the parents is a mere gratuitous assumption to fit the theory that the embryonic cell lacks organic power. The fundamental organ that conserves the body in its very existence under the government of the soul is the apparatus which effects metabolism. Incessant chemico-vital change is a characteristic of all living substances, from the single cell up to the adult man; and in all cases this activity has to do with a transformation of the complex molecules which build up the protoplasm or are associated with its operations. The totality of the chemical changes, or exchanges, in living cells, the transformation of unorganized food materials so that these may be assimilated, and the chemical processes in the tissues themselves, all are metabolism. Growth and repair (anabolism) occur side by side with the destruction of elementary tissue substance (katabolism), and the duration of life rests on these processes; and all are mere cell activities. Food-stuffs (water, inorganic salts, proteids, albuminoids, carbohydrates, and fats) undergo more or less combustion or oxidation. Oxygen unites with carbon to form carbon dioxide, and with hydrogen to form water; the nitrogen of the highly complex proteid substances reappears in combination with carbon, hydrogen, and oxygen as urea, uric acid, and other compounds; and other ingesta are thus transformed through oxidation. All maintain the temperature of the body, replace outworn parts, and accomplish the body's work. Oxidation occurs to a slight extent in the blood, but the specific reactions are intracellular. Even when nothing exists but the cells and the blood, as in the beginning embryo, the cells really do the work, and they do the work as they do in the adult.
The cells also from the very beginning are the organs that make the animal heat necessary for life. Rubner[52] proved that the source of at least 90 per cent. of the animal heat in the body is a result of the chemical changes—oxidation—in the food ingested: the other 10 per cent. is caused by muscular contractions, the flow of blood, the friction of joints, and like motions. This oxidation is more active in young animals than in adults, and in each it is, of course, a cellular process.
Living matter contains hydrogen, oxygen, sulphur, chlorine, iodine, fluorine, nitrogen, phosphorus, carbon, silicon, potassium, sodium, calcium, magnesium, and iron. The removal of one of these elements causes the death of the body. They must be arranged in a definite, prescribed order to constitute cellular protoplasm, and any disarrangement of this order causes intoxication, disease, or death. Hydrogen is a constant product in the putrefaction of animal matter, of animal food, and is present in the intestinal tract. Oxygen is found dissolved in water and loosely combined in blood as oxyhemoglobin. All the elements, except fluorine, combine with oxygen, forming oxides, and the process is called oxidation. The production of heat and all vital motion depend on oxidation, decomposition of matter. In the nuclei of cells there is a so-called "oxygen-carrier," a nucleo-proteid, which contains iron, and this appears to be the chief oxidizing agent in the body. Chlorine, which in hydrochloric acid is essential to digestion, is ingested as chloride, and leaves the body chiefly through the urine and sweat. Iodine is a necessary part of the thyroid gland, an indispensable vital organ. Fluorine is found in all cells. Nitrogen goes into the body combined in proteids; and phosphorus, combined in the alkalies and alkaline earths of the foods. Carbon occurs in all cells and leaves them through the lungs as carbon dioxide.
The amount of energy set in action in the body in the decomposition of any food is equal to the energy that had been expended in the synthesis of that food from its organic elements, and the liberated energy set free in the body appears as heat, work, and nervous impulse. In a plant the chlorophyl and the sun's rays combine water and the carbon dioxide of the air into sugar and free oxygen. This sugar is changed in a plant into starch, cellulose, and fat, and also, when combined with some nitrogen, into proteid. An animal eats this plant, which contains starch, cellulose, fat, and proteid, and it either adds these ingredients to its own substance or oxidizes them so as to prevent the destruction of its own substance. These are the ends of all food. Broadly speaking, plants synthesize elements; animals analyze them, reduce them into simpler bodies.
Such processes, and those of the other elements of the body, which have to do with the changing constituents of the human organism, are all cellular processes—metabolism. Hence the chief organic act of the body is metabolic; the basic organ of man is the cell. Arms, legs, heart, brain, stomach, and similar organs are secondary, though some of the latter are essential for certain operations. Now, one cell is an organ amply sufficient for metabolism, for the chief organic act of the body; hence it is a fitting receptacle for a substantial form, a soul. Therefore there is no reason why the soul may not be present in the one-cell stage of the embryo; and since there is no reason why it should not be present, but many why it should, it is present.
Conklin says:[53] "The fertilized egg of a star-fish, or frog, or man is not a different individual from the adult form into which it develops, rather it is a star-fish, a frog, or a human being in the one-celled stage. This fertilized egg fuses with no other cells, it takes into itself no living substance, but manufactures its own protoplasm from food substances; it receives food and oxygen from without and it gives out carbonic acid and other waste products; it is sensitive to certain alterations in the environment, such as thermal, chemical, and electrical changes—it is, in short, a distinct living thing, an individuality. Under proper environmental conditions this fertilized egg-cell develops, step by step, without the addition of anything from the outside except food, water, oxygen, and such other raw materials as are necessary to the life of any adult animal, into the immensely complex body of a star-fish, a frog, or a man. At the same time, from the relatively simple reactions and activities of the fertilized egg there develop, step by step, without the addition of anything from without except raw materials and environmental stimuli, the multifarious activities, reactions, instincts, habits, and intelligence of the mature animal."
An objection to the opinion that the soul is in the embryo from the beginning is made from a consideration of the facts that there appears to be an aptitude for life in certain animal cells and tissues after removal from the original host, or after the death of the host; and, secondly, that in other separated tissues life is undoubtedly made evident under proper conditions. Some parts of the human body can be grafted upon another human body, and human sarcomatous cells have been made to grow in vitro. Hair often lengthens after the death of a person, if no embalming fluid has been injected. Dr. Alexis Carrel[54] substituted a piece of a popliteal artery, taken from an amputated human leg and kept in cold storage for twenty-four days, for a part of the aorta of a small bitch, and the dog lived for four years afterward and died in parturition. Magitot of Paris, in 1911, took a piece of the cornea from an extirpated human eye, and with it replaced a part of an opaque cornea on another man, and this second man could see through the new cornea. Surgeons now remove skin, bone, and other tissues from still-born infants and accident cases, preserve these, for weeks if necessary, in petrolate and Ringer's solution in cold storage, and then graft them on patients to repair lesions in skin, bone, cartilage, or other parts of the body.
If these separated tissues are alive, what is the origin and nature of the life? Again, if there is a low form of life in these separated tissues, remaining after the departure of the human soul, why could not such a low form of life precede in the embryo the advent of the human soul?
What is the nature of the "life" in the parasitic sarcomatous tissue which has been seen to proliferate for a short time in vitro? We do not know, nor is it relevant to the question. That there is life of any kind in the cold-storage graft of bone and skin is certainly not evident; rather every evidence points to the absence of all life. When taken out of cold storage, and the ordinary forces which corrupt a dead body are permitted to work, these grafts corrupt exactly as any part of a corpse does. That there is life of any kind in these grafts is a gratuitous assumption. In cold storage they are kept ready for assimilation into the body as food may be kept. Bone and skin grafting is merely a peculiar form of assimilation. Food taken into the body through the stomach and entrails is prepared in the body and assimilated into the substance of the bones or skin or other tissues; the graft is ready for assimilation without this preparation because it is already bone or skin.
The vital principle in a man, or in anything else, is at the end, when it normally issues, of the same nature as it was in the beginning. If it is at perfection a substantial primary form, it always was such—a substantial form cannot issue from an accidental form. If the substantial form is the form of the cells in the completed organism, it was such before that organism was perfected, unless it replaced a lower substantial form; but there is, we repeat, absolutely no need for such a secondary form at the beginning. If the cells of the embryo (not the infused germ-cells, which are not the embryo) had a forma corporeitatis, or cellularis, or whatever you wish to call it, the human soul when it did come would not confer primal existence, would not be a forma substantialis, but an accidental form. "In proof of which," says St. Thomas,[55] "we must consider that a substantial form differs from an accidental form in this, that an accidental form does not give being simply, but such or such being; as heat does not give being simply, but heated being. So when an accidental form comes in, a thing is not said to come into existence or to be generated, simply, but to become such or such an object, or to find itself in such or such a condition. So, also, when an accidental form disappears, a thing is not said to be destroyed simply, but only to a certain degree. A substantial form, however, gives being simply; and therefore by its advent a thing is said to be generated simply, and by its recession to be destroyed simply. If, therefore, it happened that any substantial form other than the intellectual soul preëxisted in matter, by which the subject of that soul would come into actual being, it would follow that the soul would not confer being simply, and therefore would not be a substantial form; also that the coming of the soul would not be a generation simply, but only secundum quid—all of which is evidently false." Again, St. Thomas says:[56] "Some tell us the vital acts that appear in the embryo are not from the soul, but from the soul of the mother, or from the primitive force in the semen. Both these statements are false."
An application of the opinion offered here—that is, that the human soul is infused at the instant of conception—to multiple and monstrous embryos offers no real difficulty. There are two kinds of human twins—those from two distinct ova and those from one ovum. Two ova may come from one or different ovaries, or even from one Graafian follicle, be fertilized at the same time and develop synchronously. If the ova are placed at some distance apart in the uterus, two placentas appear; if the ova are near each other the placentas may fuse, but their circulations do not. Each child will have its own fetal envelope.
In twins from two distinct ova there is no difficulty in seeing that the souls are placed in these in the same manner as the soul is put in the normal single embryo. When the twins come from one ovum the condition is not so simple. The oval nucleus is the essential part that goes from the maternal side, and human ova at times contain two nuclei, as occasionally hens' eggs do; a double-yoked hen's egg has two nuclei, and two nuclei have been found in a single yolk. Kölliker, Stöckel, and von Franque have observed double germinal vesicles in single human ova. In such a condition two spermatozoa could fecundate the two nuclei and the development go on as in the case of twins from distinct ova.
There is a theory which holds that homologous twins (uni-oval) can develop from a single germinal vesicle which splits into two primitive streaks and two gastrulas. According to this opinion, if the germinal vesicle divide entirely, two fetuses develop which are always of the same sex, and which resemble each other so closely in appearance that it is very difficult to differentiate them. This theory holds also that should the germinal vesicle not split fully, the lack of fission causes the various kinds of double monsters. The germinal vesicle that supposedly splits into two is not fecundated by two spermatozoa, they say, because where there is only one nucleus in the beginning, the entrance of a second spermatozoön commonly kills the ovum. This last assertion has been disproved of late.
Some followers of the splitting theory hold that double monsters arise from the union of two originally separate primitive traces (Verwachsungstheorie). Others say that a single primitive trace of blastoderm cleaves more or less thoroughly and makes the double monster (Spaltungstheorie). The earliest human double monster (Ahlfeld's case) was in the fourth week of gestation; therefore whatever is held in these theories as regards human monsters is only through analogy with lower animals.
Gerlach[57] saw bifurcation at the cephalic end of a chicken embryo sixteen hours old. In this case the first change was a broadening of the anterior end of the primitive streak; next a forked divergence appeared, and by the twenty-sixth hour the bifurcation was half as long as the undivided posterior part. Whether this was a case of two nuclei or not is not known.
What seems to make for the fission theory is that in non-parasitic double terata, no matter how unequally nourished or how variable in extent, the union between the halves of double monsters is symmetric, and the same part of each twin is joined. This fact is used as a reason to exclude a fortuitous growing together of dissimilar areas of cell-masses, at least in non-parasitic cases. Born,[58a] in a study of fish ova, found that eggs which produce double monsters begin with a segmentation like that of the simple normal ovum. Composite spermatozoa have been observed with two and three heads and one body and tail-piece, but the significance of these abnormal cells is not known.
Embryos of sea-urchins in the two-cell and four-cell stages can be separated by shaking into isolated blastomeres, and the segments will grow into full though dwarfed larvae. The same division with the growth of dwarfed larvae has been made in Amphioxus, in the teleost Fundulus, in Triton, in a number of Hydromedusae and several other low forms of life. When the division is not made completely double monsters result.
Up to a certain stage of development the blastomeres of the Medusa embryo are totipotent, or capable of developing into any part of the body. The limitation of development in a particular case lies in the cytoplasm rather than in the nuclei of the cells. If frogs' eggs are fastened in abnormal positions, inverted or on the side, a rearrangement of the egg material results, wherein the nucleus and cytoplasm rise and the deutoplasm sinks. This change of axis shifts the embryo. If an egg is turned upside down in the two-cell stage, a whole embryo, or half a double embryo, may arise from each of the two blastomeres, instead of a normal half-embryo. A half-embryo or a whole dwarf may arise according to the artificial position of the blastomere. Each of the two blastomeres contains all the materials potentially for the formation of the whole body, and these materials build up a whole body or a half body according to the grouping they take on. Primarily the egg cytoplasm, in low forms of animal life, is totipotent; it has no fixed relation with the parts to which it gives rise, and may be artificially modified or differentiated. These effects, from position and traumatic dislocation, suggest explanations for teratic forms in higher animals.
Human terata are now commonly classified in four groups: (1) Hemiteratic; (2) Heterotaxic; (3) Hermaphroditic; and (4) Monstrous. Hemiterata are giants, dwarfs, persons showing anomalies in shape, color, closure of embryonal clefts, in absence or excess of digits, or like defects. The Heterotaxic group are persons whose left or right organs are reversed in position. A true Hermaphrodite would have the complete reproductive organs of both sexes, but such an individual has not been observed. There is never any question of double personality in hermaphrodites.
Terata more properly so called may be single, double, or triple; and single monsters may be autositic or independent of another fetus, or they may be omphalositic, dependent upon another which is commonly well developed and which supplies blood for both through the umbilical vessels. There are four genera of autositic single monsters, with eight species and thirty-four varieties. Of the monstra per defectum the commonest are caused by a failure of closure in the embryonal medullary canal, which leaves part of the brain and spinal cord or their bony covering lacking. Some terata, as the Acephalia, have no brain or spinal cord, but they die in the fetal stage. The Anencephalia may have a spinal cord, a medulla oblongata, and parts of the basal ganglia, but the cerebral hemispheres are wanting. Such monsters are sometimes born at term and live for several days: they cry, suckle, show some reflexes and a sense of pain, and move the arms and legs.
I described the various kinds of terata in Essays in Pastoral medicine,[58b] and of these the most important in the matter under discussion here are the double and triple monsters. Many of the double monsters evidently were two persons. There is only one well authenticated case of a triple human monster, and this happened in Italy in 1831. It had a single broad body with three distinct heads and two necks, and was killed in delivery. There is no proof as to whether it was one or more persons. The standard of judgment in such cases as regards the presence of one or two souls in the monster is the evidence of one or more distinct consciousnesses. A monster double from the navel or breast downward (terata anadidyma) is, I think, one person. There was an example of a monster in this group which was divided from the foreheads downward; or better, the distinct twins were united by their foreheads only; but such a form is very exceptional. In my article on "Human Terata and the Sacraments," in Essays in Pastoral Medicine, in 1906, I expressed the opinion that a monster which is single to the navel and double below is composed of two persons, but I now am of the opinion that such a monster is only one person, because there is apparently only one consciousness. There are about eight cases of two-headed monsters known which were evidently two persons in each case, and several terata kata-anadidyma, divided above and below but joined at the sternum, abdomen or sacrum. Several ischiopagic twins, joined at the pelvis with the heads at the opposite ends of the double body, are grouped with either the katadidyma or kata-anadidyma. It is commonly not difficult to recognize individuality or duality of personality in monsters, but it is not easy to explain the origin of life, to point out the moment the second soul enters these fused or undivided twins.
We can artificially obtain double embryos of frogs by inverting the blastomeres in the two-cell stage.[58c] We thus get united twins with heads turned in opposite directions, twins united back to back like the Blazek Sisters, twins united by their ventral sides, and double-headed tadpoles, but we have no knowledge of how similar doubling in human monsters takes place; we must guess vaguely from analogy. There was one soul, at least, present from the one-cell stage of the human monster; when the second soul is created and infused we do not know, but the moment of the creation of this second soul has no practical significance in this discussion.
The presence of certain kinds of monsters in the uterus can be diagnosed before labor, but double monsters are mistaken for ordinary twins. A woman who has given birth to a monster is likely to have subsequent monstrous fetuses. Where the intrauterine existence of a single monster is suspected the X-ray will at times clear up the diagnosis. Women gravid with monsters commonly abort early in pregnancy, but even united twins may go on to term. Those monsters that offer an obstacle to delivery by the abnormal bulk of one or the other end are mostly twins joined above or below the navel; those joined at the middle are easier of delivery. Monsters that are joined at the pelves are commonly in a straight line, and may not be difficult to deliver. Most double monsters cannot be delivered alive except by cesarean section, and the fact that the content of the uterus is monstrous is, as a rule, not diagnosed until it is impossible to attempt cesarean section without killing the mother through infection. In such a condition the double monster would, in the ordinary medical practice, be delivered by craniotomy, exenteration, cleidotomy, or the like operation.
The Rituale Romanum Pauli V[59] gives the following directions for the baptizing of human terata:
"18. In monstris vero baptizandis, si casus eveniat, magna cautio, adhibenda est, de quo si opus fuerit, ordinarius loci, vel alii periti consulantur, nisi mortis periculum immineat.
"19. Monstrum, quod humanam speciem non praeseferat baptizari non debet; de quo si dubium fuerit, baptizatur sub hac conditione; Si tu es homo ego te baptizo, etc.
"20. Illud vero, de quo dubium est, una ne, aut plures sint personae non baptizetur, donee id discernatur: discerni autem potest si habeat unum vel plura capita, unum vel plura pectora; tune enim totidem erunt corda et animae, hominesque distincti, et eo casu singuli seorsim sunt baptizandi, unicuique dicendo: Ego te baptizo, etc. Si vero periculum mortis immineat, tempusque non suppetat, ut singuli separatim baptizentur, poterit minister singulorum capitibus aquam infundens omnes simul baptizari, dicendo: Ego vos baptizo in nomine Patris, et Filii, et Spiritus Sancti. Quam tamen formam in iis solum, et in aliis similibus mortis periculis, ad plures simul baptizandos, et ubi tempus non patitur, ut singuli separatim baptizentur, aliis nunquam, licet adhibere.
"21. Quando vero non est certum in monstro duas esse personas, ut quia duo capita et duo pectora non habet distincta; tune debet primus unus absolute baptizari, et postea alter sub conditione, hoc modo: Si non es baptizatus, ego te baptizo in nomine Patris, et Filii, et Spiritus Sancti."
Any kind of monster coming from the human womb, if it is only a head and lacks a body (Acardiacus Acormus), or is a body and lacks a head and heart (Acardiacus Acephalus), or is a Foetus Anideus, which is a shapeless mass of flesh covered with skin, should be baptized, provided it shows signs of life. Number 19 in the Ritual would be liable to an interpretation which is too narrow if it were not that very monstrous fetuses, which appear to a lay observer to be not human, are as a rule delivered dead. Here it may be worth while to mention that a hybrid between a human being and a lower animal is impossible. As to number 20, the rule for differentiating unity or duality of personality is not the number of heads, but the number of evident consciousnesses, and this differentiation commonly cannot be made at birth. There have been examples of two-headed monsters delivered alive, which were single as to soul because the consciousness evidently was one.