Among the numerous classes of higher animals, which have red blood, we have heard of no well-authenticated instance of hermaphrodism, or the complete union of all the reproductive organs in one individual. True, the term hermaphrodite is often applied to certain persons in whom there is some malformation, deficiency, or excess, of the genital organs. These congenital deformities consisting of combined increase or deficiency, supernumerary organs, or transposition of them, which usually render generation physically impossible, have been called bisexual hermaphrodism and classed as monstrosities. We have many published accounts of them, hence, further reference to them here is unnecessary. We would especially refer those readers who may desire to make themselves further acquainted with this interesting subject, to the standard physiological works of Flint, Foster, Carpenter, Bennett, Dalton, and others equally eminent in this particular branch of science.
Certain theories have been advanced concerning conditions which may influence the sex of the offspring. One is that the right ovary furnishes the germs for males, the left for females that the right testicle furnishes sperm capable of fecundating the germs of males, and the left testicle, the germs of the left ovary, for females. That fecundation sometimes takes place from right to left and thus produces these abnormal variations. We merely state the hypothesis, but do not regard it as accounting for the distinction of sex, or as causing monstrosities, though it is somewhat plausible as a theory, and is not easily disproved. In the lower order of animals, as sheep and swine, one of the testicles has been removed, and there resulted afterward both male and female progeny, so that the theory seems to lack facts for a foundation.
We sometimes witness in the child excessive development, as five fingers, a large cranium, which results in dropsical effusion, or deficient brain, as in idiots; sometimes a hand or arm is lacking, or possibly there is a dual connection, as in the case of the Siamese twins; or, two heads united on one body. It is difficult to give any satisfactory explanation of these abnormal developments. From age to age, the type is constant, and preserves a race-unity. The crossings of the races are only transient deviations, not capable of perpetuation, and quickly return again to the original stock. This force is persistent, for inasmuch as the individual represents the race, so does his offspring represent the parental characteristics, in tastes, proclivities, and morals, as well as in organic resemblances. This constancy is unaccountable, and more mysterious than the occasional malformation of germs in the early period of foetal life. If to every deviation from that original form and structure, which gives character to the productions of nature, we apply the term monster, we shall find but very few, and from this whole class there will be a very small number indeed of sexual malformations. If the sexes be deprived of the generative organs, they approach each other in disposition and appearance. All those who are partly male and partly female in their organization, unite, to a certain extent, the characteristics of both sexes. When the female loses her prolific powers, many of her sexual peculiarities and attractions wane.
DIOECIOUS REPRODUCTION.
Dioecious is a word derived from the Greek, and signifies two households; hence, dioecious reproduction is sexual generation by male and female individuals. Each is distinguished by sexual characteristics. The male sexual organs are complete in one individual, and all the female organs belong to a separate feminine organization. In some of the vertebrates, impregnation does not require sexual congress; in other words, fecundation may take place externally. The female fish of some species first deposits her ova, and afterwards the male swims to that locality and fertilizes them with sperm.
In higher orders of animals, fecundation occurs internally, the conjunction of the sperm and germ cells requiring the conjugation of the male and female sexual organs. The sperm-cells of the male furnish the quickening principle, which sets in play all the generative energies, while the germ-cell, susceptible to its vivifying presence, responds with all the conditions necessary to evolution. The special laboratory which furnishes spermatic material is the testes, while the stroma of the ovaries contributes the germ-cell. Several different modes of reproducing are observed when fecundation occurs within the body, which vary according to the peculiarities and organization of the female.
Modes of Dioecious Reproduction.—A very familiar illustration of one mode is found in the common domestic fowl, the egg of which vivified within the ovarium, is afterward expelled and hatched by the simple agency of warmth. This mode of reproduction is called oviparous generation.
The ovaries, as well as all their latent germs, are remarkably influenced by the first fecundation. It seems to indicate monogamy as the rule of higher sexual reproduction. The farmer understands that if he wishes to materially improve his cows, the first offspring must be begotten by a better, purer breed, and all that follow will be essentially benefited, even if not so well sired. Neither will the best blood exhibit its most desirable qualities in the calves whose mothers have previously carried inferior stock. So that there are sexual ante-natal influences which may deteriorate the quality of the progeny. The Jews understood this principle, in the raising up of sons and daughters unto a deceased brother. The fact that the sexual influence of a previous conception is not lost, is illustrated when, in a second marriage, the wife bears a son or daughter resembling bodily or mentally, or in both of these respects the former husband. This indicates a union for life by natural influences which never die out.
With some species of fish and reptiles, the egg is impregnated internally, and the process of laying commences immediately, but it proceeds so slowly through the excretory passages, that it is hatched and born alive. This is called ovo-viviparous generation.
As we rise in the scale of organization, animals are more completely developed, and greater economy is displayed in their preservation. The germ passes from the ovary into an organ prepared for its reception and growth, to which, after fecundation, it becomes attached, and where it remains until sufficiently developed to maintain respiratory life. This organ is called the womb, or uterus, and is peculiar to most mammalia. This mode of reproduction is termed viviparous generation.