NOTES
[A]An interesting problem concerning the atmosphere is suggested by certain geological facts. In our buried coal-seams and other carbonaceous deposits a great quantity of carbon, for the most part abstracted from the atmosphere, has been stored away. Still greater quantities of carbon are imprisoned in the substance of our limestones, which contain, when pure, 44 per cent. of this element. A large quantity of oxygen has also been taken from the atmosphere to combine with other elements during their oxidation. The question is—Was the atmosphere, in the geological past, more richly laden with carbonic acid gas, of which some has entered into combination with lime to form limestone, while some has been decomposed by plants, the carbon being buried as coal, and the oxygen as products of oxidation? Or, has the atmosphere been furnished with continuous fresh supplies of carbonic acid gas?
[B]It has before been noticed that the organs themselves have their periods of rest. The rhythm of rest and repose in the heart is not that of the activity and sleep of the organism, but that of the contraction and relaxation of the organ itself.
[C]From a popular article of the author's on "Horns and Antlers," in Atalanta.
[D]It will be well here to introduce the technical terms for these changes. The general term for chemical actions occurring in the tissues of a living creature is metabolism; where the change is of such a nature that complex and unstable compounds are built up and stored for a while, it is called anabolism; where complex unstable compounds break up into less complex and relatively stable compounds, the term katabolism is applied. We shall speak of anabolic changes as constructive; katabolic, as disruptive, or sometimes, explosive.
[E]I do not mean, of course, to imply that there is no reconstruction during activity, but that it is then distinctly outbalanced by disruptive changes.
[F]Professor Geddes and Mr. J. Arthur Thomson, in their interesting work on "The Evolution of Sex," regard the ovum in especial, and the female in general, as preponderatingly anabolic (see note, [p. 32]); while the sperm in especial, and the male in general, are on their view preponderatingly katabolic. Regarding, as I do, the food-yolk as a katabolic product, I cannot altogether follow them. The differentiation seems to me to have taken place along divergent lines of katabolism. In the ovum, katabolism has given rise to storage products; in the sperm, to motor activities associated with a tendency to fission. The contrast is not between anabolic and katabolic tendencies, but between storage katabolism and motor katabolism. Nor do I think that "the essentially katabolic male-cell brings to the ovum a supply of characteristic waste products, or katastates, which stimulate the latter to division" (l.c., [p. 162]). I believe that it brings an inherited tendency to fission, and thus reintroduces into the fertilized ovum the tendency which, as ovum, it had renounced in favour of storage katabolism.
[G]On the other hand, three ova of the crustacean Apus are said to coalesce to form the single ovum from which one embryo develops.
[H]"The Evolution of Sex," [p. 84].
[I]In some forms of life the opening of the cup marks the position of the future mouth: in others, of the future vent. In yet others it elongates into a slit, occupying the whole length of the embryo; the middle part of the slit closes up, and the opening at the far ends mark the position, the one of the future mouth, the other of the future vent.
[J]In technical language, the outer layer of cells is called the epiblast, the inner layer the hypoblast, and the mid-layer between them the mesoblast.
[K]In technical language, the opening by which the primitive digestive cavity (or mesenteron) communicates with the exterior is called the blastopore. When this closes, the new opening for the mouth is called the stomodœum; that for the vent, the proctodœum.
[L]We have seen that when volume tends to outrun surface, fission may take place, whereby the same volume has increased surface. But in unfavourable nutritive conditions, the same surface which had before been sufficient for nutrition may become, under the less favourable circumstances, insufficient, and fission may again take place to give a larger absorbent surface. Hence, possibly, the connection between insufficient nutriment and highly subdivided sperms.
[M]Samuel Butler in England, and Ewald Hering in Prague, have ingeniously likened this hereditary persistence to "organic memory." What are ordinarily called memory, habit, instinct, and embryonic reconstruction, are all referable to the memory of organic matter. The analogy, if used with due caution, is a helpful one, what we call memory being the psychical aspect (under certain special organic and neural conditions) of what under the physical aspect we call persistence.
[N]I have also to thank Mr. Edward Wilson for kindly giving me the measurements of three or four bats in the Bristol Museum.
[O]A millimetre is about 1/25 of an inch, or more exactly .03937 inch.
[P]In nearly all cases the measurements were checked by comparing the two wings. In one or two instances there were differences of as much as two or three millimetres between the bones of the two sides of the body, but in most cases they exactly corresponded.
[Q]We are anxious to extend our observations and to compare series of bats from different localities. If any of my readers should feel disposed to help us, by sending specimens (with the locality duly indicated) to Mr. H. Charbonnier, 7, The Triangle South, Clifton, Bristol, we shall be grateful.
[R]Nature, vol. xli. p. 393. The variation in molluscs is often considerable. In one of the bays in the basement hall of the Natural History Museum is a series showing the variation in size, form, and sculpturing of Paludomus loricatus, which is found in the streams of Ceylon. These varieties have in former times been named as ten distinct species!
[S]More observations and fuller knowledge on this latter point and on the relative numbers of the sexes in different species are much to be desired. It is clear that the number of offspring mainly depends upon the number of females. But if it be true that good times and favourable conditions lead to an increased production of females, while hard times and unfavourable conditions lead to a relative increase of males, then it is evident that good times will lead to a more rapid increase and hard times to a less rapid increase of the species. Suppose, for example, in a particular district food and other conditions were especially favourable for frogs. Among the well-nourished tadpoles there would be a preponderance of females. In the next generation the many females would produce abundant offspring (for one male may fertilize the ova laid by several females). There would be a greater number of tadpoles to compete for the same amount of nutriment. They would be less nourished. There would be less females; and in the succeeding generation a diminished number of tadpoles. Thus to some extent a balance between the number of tadpoles and the amount of available nutrition would be maintained. These conclusions are, perhaps, too theoretical to be of much value, while the tendency here indicated would be but one factor among many.
[T]"Origin of Species," pp. 62, 63.
[U]"Animals and Plants under Domestication," vol. ii. p. 177.
[V]I may here draw attention to the fact that the bats whose wing-bone measurements were given above are those which have so far survived and escaped such elimination as is now in progress.
[W]"Origin of Species," p. 109.
[X]"Darwinism," p. 106.
[Y]Ibid. p. 106.
[Z]Proceedings Liverpool Biological Society, 1889.
[AA]Since this chapter was written, Mr. Poulton has published his interesting and valuable work on "The Colours of Animals," from which I have contrived to insert one or two additional examples.
[AB]Ann. and Mag. Nat. Hist., September, 1889, p. 209, quoted by Poulton, "Colours of Animals," p. 55.
[AC]Nature, vol. xxxv. p. 77.
[AD]Many other instances might be added. The hornet clear-wing moth (Sphecia apiformis) mimics the hornet or wasp; the narrow-bordered bee-hawk moth (Sesia bombyliformis) mimics a bumble-bee. These insects may be seen in the lepidoptera drawers in the Natural History Museum. But perhaps the most wonderful instance of insect-mimicry is that observed by Mr. W. L. Sclater, and given by Mr. E. B. Poulton, in his "Colours of Animals" (p. 252), where a (probably) homopterous insect mimics a leaf-cutting ant, together with its leafy burden—a membranous expansion in the mimic closely resembling the piece of leaf carried by the particular kind of ant he resembles.
[AE]The late Mr. H. W. Oakley first drew my attention to this snake. Since then Mr. Hammond Tooke has described the facts in Nature, vol. xxxiv. p. 547.
[AF]Nature, vol. xlii. p. 115.
[AG]Since the above was written and sent to press, there has been added, at the Natural History Museum, in the basement hall, a case illustrating the adaptation of external colouring to the conditions of life. All the animals, birds, etc., there grouped were collected in the Egyptian desert, whence also the rocks, stones, and sand on which they are placed were brought. Though somewhat crowded, they exemplify protective resemblance very well.
[AH]I have to thank Mr. H. A. Francis for drawing my attention to this, and showing me the insects in his cabinet.
[AI]"Colours of Animals," p. 73.
[AJ]"Origin of Species," p. 161.
[AK]"Descent of Man," summary of chap. xvi. pt. ii.
[AL]Ibid. chap. xiv.
[AM]"Darwinism," p. 108.
[AN]Its importance in artificial selection was emphasized by Darwin: "The prevention of free crossing, and the intentional matching of individual animals, are the corner-stones of the breeder's art" ("Animals and Plants under Domestication," ii. 62).
[AO]From the absence of interblending in some cases (to be considered shortly), both brown and green forms may be produced; and under certain circumstances, even a power of becoming either brown or green in the presence of appropriate stimuli.
[AP]Wallace, "Darwinism," p. 172, where other examples are cited.
[AQ]Ibid. pp. 217, et seq.
[AR]Journal of the Linnæan Society, vol. xix. No. 115: "Zoology."
[AS]"Animals and Plants under Domestication," p. 145.
[AT]Ibid. chap. xvii.
[AU]"Darwinism," p. 326.
[AV]"Animals and Plants under Domestication," vol. ii. p. 65. For Darwin's general conclusions on hybridism, see vol. ii. p. 162 of the same work.
[AW]"In every case there are two factors, namely, the nature of the organism and the nature of the conditions. The former seems to be much the more important; for nearly similar variations sometimes arise under, as far as we can judge dissimilar conditions; and, on the other hand, dissimilar variations arise under conditions which appear to be nearly uniform" ("Origin of Species," p. 6).
[AX]See "Evolution without Natural Selection," by Charles Dixon. This author's facts are valuable; his theories are ill digested.
[AY]Nature, vol. xlii. p. 136.
[AZ]We may here note, in passing, the fact that the changes of life-forms in a succession of beds points in nine cases out of ten rather to substitution through migration than to transmutation. Still, there are notable cases of transmutation, as in the fresh-water Planorbes of Steinhem, in Wittenberg (described, after Hilgendorf, by O. Schmidt, "The Doctrine of Descent," p. 96).
[BA]I would ask historians whether there have not been, in English history, good times of free and beneficial divergence exemplified in diverse intellectual activity, hard times of rigorous elimination, and intermediate times of placid, somewhat humdrum conservatism.
[BB]Two more technical examples may be noticed in a note. (1) Professor Haeckel has recently (Challenger Reports, vol. xxviii.) shown that the Siphonophora include two groups, closely resembling each other, but of different ancestry: (a) The Disconanthæ, traceable to trachomedusoid ancestors; (b) the Siphonanthæ, traceable to anthomedusoid ancestors like Sarsia. (2) M. Paul Pelseneer has been led to the conclusion that the pteropod molluscs also include two groups resembling each other, but of different ancestry: (a) The Thecosomes, traceable to tornatellid ancestors; (b) the Gymnosomes, traceable to aphysiid ancestors. In each case, the ancestral sea-slug has been modified for a free-swimming life.
[BC]For evidence in copious abundance, see Nicholson's "Manual of Palæontology," new edition, vol. i.: "Vertebrata," by R. Lydekker.
[BD]"Animals and Plants under Domestication," vol ii. p. 239.
[BE]Or in certain "physiological units" (Herbert Spencer), or "plastidules" (Haeckel), which may be regarded as organic molecules exhibiting their special properties under vital conditions.
[BF]Nature, vol. xxxix. p. 486.
[BG]Darwin, "Animals and Plants under Domestication," 2nd edit., vol. ii. chap. xxvii., from which the following description and quotations are taken.
[BH]For an excellent account of the genesis and growth of the modern views of heredity, see Mr. J. Arthur Thomson's paper on "The History and Theory of Heredity:" Proceedings of the Royal Society of Edinburgh, 1889.
[BI]Geddes and Thomson, "The Evolution of Sex," p. 92.
[BJ]Weismann, "Essays on Heredity," English translation, p. 173.
[BK]Weismann, "Essays on Heredity," p. 205.
[BL]A few pages earlier (p. 200) in the same essay, Professor Weismann says, "A sudden transformation of the nucleo-plasm of a somatic cell into that of a germ-cell would be almost as incredible as the transformation of a mammal into an amœba." This at first sight does not seem quite consistent with the subsequent sentence which I have quoted in the text; for here, at any rate, the daughters of "mammals" are said to be converted into "amœbæ." But this is no doubt because the amœbæ (germ-plasms) are contained in the mammals (body-cells). (See the quotations that follow in the text.)
[BM]Weismann, "Essays on Heredity," p. 207.
[BN]Weismann, "Essays on Heredity," p. 179.
[BO]It will, of course, be understood that a minute fragment of germ-plasm is capable of almost unlimited growth by assimilation of nutritive material, its properties remaining unchanged during such growth.
[BP]Latency is here neglected. Mr. Francis Galton has shown, statistically, that the offspring, among human folk, inherit 1/4 from each parent, 1/16 from each grandparent, and the remaining 1/4 from more remote ancestors. In domesticated animals, reversion to characters of distant ancestors sometimes occurs. This, however, does not invalidate the argument in the text, which is that sexual admixture tends towards the mean of the race (ancestors included), and cannot be credited with new and unusually favourable variations. The prepotency of one parent is also here neglected.
[BQ]See his valuable paper on "Divergent Evolution," Lin. Soc. Zool., No. cxx.
[BR]One parthenogenetic form—the drone—has been shown by Blochmann to extrude a second polar cell. This observation is in serious opposition to Dr. Weismann's theory.
[BS]Weismann, "Essays on Heredity," pp. 355, 378.
[BT]The law of compensation of growth or balancement was suggested at nearly the same time by Goethe and Geoffrey Saint-Hilaire. The application in the text has not, so far as I know, been before suggested.
[BU]Darwin spoke of changed conditions acting "directly on the organization or indirectly through the reproductive system." Now, since Professor Weismann has taught us to reconsider these questions, we speak of such conditions as acting directly on the germ or indirectly through the body. The germ is no longer subordinate to the body, but the body to the germ.
[BV]July 15, 1876. Since reprinted in "The Advancement of Science," p. 273.
[BW]Herbert Spencer, "Principles of Biology," vol. i. p. 256.
[BX]Mr. J. A. Thomson has published a most valuable "Synthetic Summary of the Influence of the Environment upon the Organism" (Proceedings Royal Physiological Society, Edinburgh: vol. ix. pt. 3, 1888). The case of the Amazonian parrots was communicated to Darwin by Mr. Wallace ("Animals and Plants under Domestication," vol. ii. p. 269).
[BY]St. George Mivart, "On Truth," p. 378.
[BZ]Op. cit., p. 47. I venture to say, "with some assurance," because Charles Darwin, who had also considered this matter, writes, "Who will pretend to decide how far the thick fur of Arctic animals, or their white colour, is due to the direct action of a severe climate, and how far to the preservation of the best-protected individuals during a long succession of generations?" ("Animals and Plants under Domestication," p. 415).
[CA]"Organic Evolution," English translation, p. 88.
[CB]"Contributions to Natural Selection," p. 197.
[CC]Since this was written, Mr. Poulton has described his results in an interesting volume on "The Colours of Animals" (q.v.).
[CD]See Journal of Anatomy and Physiology, vol. xxii. p. 215.
[CE]See Professor Herdman's Inaugural Address, Liverpool Biological Society, 1888.
[CF]Francis Galton, "Inquiries into Human Faculty," p. 216.
[CG]That the epidermis is thicker on the palms of the hands and the soles of the feet in the infant long before birth, may be attributable to the inherited effects of use or pressure. It can hardly be held that the thickening of the skin in these parts is of elimination value.
[CH]The instances cited are from "Animals and Plants under Domestication."
[CI]It is beyond the scope of this book to give the evidences of evolution. Such evidence from embryology, from distribution, and from palæontology, is now abundant. For palæontological evidence, see Nicholson's "Manual of Palæontology," 3rd edit., especially the second volume on "Vertebrates," by R. Lydekker.
[CJ]Weismann, "Essays on Heredity," p. 24.
[CK]Ibid. p. 140.
[CL]Weismann, "Essays on Heredity," p. 90.
[CM]Ibid. p. 292. See also a discussion in Nature, in which Mr. Romanes and Professor Ray Lankester took part, beginning vol. xli. p. 437.
[CN]Weismann, "Essay on Heredity," p. 140.
[CO]"Origin of Species," p. 110.
[CP]With regard to blind cave-fish, Professor Ray Lankester has suggested that some selection has been effected. Those animals whose sight-sensitiveness enabled them to detect a glimmer of light would escape to the exterior, leaving those with congenitally weak sight to remain and procreate in the darkness of the cave.
[CQ]Darwin, "Descent of Man," pt. ii. chap. viii.
[CR]"Darwinism," chap. x.
[CS]"Darwinism," p. 295. Messrs. Geddes and Thomson, "The Evolution of Sex," p. 28, also contend that "combative energy and sexual beauty rise pari passu with male katabolism."
[CT]"Darwinism," p. 293.
[CU]Mr. Poulton, who takes a similar line of argument in his "Colours of Animals," lays special stress upon the production of white (see p. 326).
[CV]See Chapter VIII.
[CW]"Darwinism," p. 172.
[CX]See "Animals and Plants under Domestication," vol. ii. p. 80.
[CY]"Darwinism," p. 332.
[CZ]"The Colour-Sense," by Grant Allen, p. 95.
[DA]That on "The Emotions of Animals" (X.).
[DB]"Darwinism," p. 318.
[DC]Natural History Society of Wisconsin, vol. i. (1889).
[DD]"Darwinism," p. 286.
[DE]On the negative character of disuse, see p. 196.
[DF]Cope, "Origin of the Fittest," p. 374.
[DG]It would appear, from certain passages of his "Darwinism," that Mr. A. R. Wallace (e.g. p. 139, note) holds or held similar views. "The genera Ateles and Colobus," he says, "are two of the most purely arboreal types of monkeys, and it is not difficult to conceive that the constant use of the elongated fingers for climbing from tree to tree, and catching on to branches while making great leaps, might require all the nervous energy and muscular growth to be directed to the fingers, the small thumb remaining useless." I should also have quoted Mr. Wallace's account of the twisting round of the eyes of flat-fishes—where he says that the constant repetition of the effort of twisting the eye towards the upper side of the head, when the bony structure is still soft and flexible, causes the eye gradually to move round the head till it comes to the upper side—had he not subsequently disclaimed this explanation (see Nature, vol. xl. p. 619). It is possible that Mr. Wallace, notwithstanding the words "constant use" in the passage I have quoted, merely intends to imply that the elongated fingers are of advantage in climbing, and are thus subject to natural selection, the thumb diminishing through economy of growth.
[DH]I find, on rereading one of his articles, that I have here unwittingly adopted one of Mr. Romance's arguments (see Nature, vol. xxxvi. p. 406). The instance Mr. Romanes cites is the curious habit of dogs turning round before they lie down.
[DI]Mr. Darwin, while contending that the modifications need not all have been simultaneous, says, "Although natural selection would thus tend to give the male elk its present structure, yet it is probable that the inherited effects of use, and of the mutual action of part on part, have been equally or more important" ("Animals and Plants under Domestication," vol. ii. p. 328).
[DJ]Midland Naturalist, November, 1889.
[DK]See ante, p. 52.
[DL]Nature, vol. xli. p. 511.
[DM]"Animals and Plants under Domestication," vol. ii. p. 291.
[DN]In the third chapter we saw that in such cases not only are there an enormous number of ova produced, but that (e.g. in aurelia and the liver-fluke) each ovum produces, through the intervention of asexual multiplication, many individuals.
[DO]Cope, "Origin of the Fittest," pp. 226, 125, and 297.
[DP]"Animals and Plants under Domestication," vol. ii. p. 313.
[DQ]Ibid. p. 56.
[DR]Nature, vol. xxxvi. p. 592.
[DS]Quoted from "Medical Notes and Reflections," 1855, p. 267, by Darwin, "Animals and Plants under Domestication," vol. i. p. 446.
[DT]Darwin, "Animals and Plants under Domestication," vol. i. p. 465.
[DU]"Natural Inheritance," p. 12.
[DV]Darwin, "Animals and Plants under Domestication," vol. ii. p. 70.
[DW]"Organic Evolution," Mr. Cunningham's translation, p. 76.
[DX]Darwin, "Animals and Plants under Domestication," vol. i. p. 104.
[DY]Similarly, from a chance sport of a one-eared rabbit, Anderson formed a breed which steadily produced one-eared rabbits ("Animals and Plants under Domestication," vol. i. p. 456). This is an example of asymmetrical variation. Variations are generally, but not always, symmetrical. Superficial colour-variations are sometimes asymmetrical. Gasteropod molluscs are nearly always asymmetrically developed. Among insects, Anisognathus affords an example of the asymmetrical development of the mandible. Our right-handedness is a mark of asymmetry.
[DZ]"Natural Inheritance," p. 32.
[EA]See "Animals and Plants under Domestication," vol. ii. p. 40, from which illustrations are taken.
[EB]"Evolution and Disease," p. 169.
[EC]"Animals and Plants under Domestication," vol. ii. p. 8.
[ED]"Darwinism," p. 107.
[EE]Darwin, "Animals and Plants under Domestication," vol. ii. pp. 17, 18.
[EF]"Animals and Plants under Domestication," vol. ii. p. 201.
[EG]Ibid. p. 282. The phenomena of the seasonal dimorphism of butterflies and moths show that changes of temperature (and perhaps moisture, etc.) determine very striking differences in these insects.
[EH]"Animals and Plants under Domestication," vol. ii. p. 244.
[EI]"Darwinism," p. 293.
[EJ]"Evolution of Sex," p. 22.
[EK]"Incidental Observations in Pedigree Moth-breeding," F. Merrifield. Transactions Entomological Society, 1889, pt. i. p. 79, et seq.
[EL]Nature, vol. xli. p. 393.
[EM]See Professor Meldola's edition of Professor Weismann's "Studies in the Theory of Descent," and Mr. Cunningham's translation of Professor Eimer's "Organic Evolution."
[EN]See Darwin, "Animals and Plants under Domestication," vol. ii. p. 252.
[EO]See abstract in Nature, vol. xxxiv. p. 515.
[EP]See Nature, vol. xxxvii. p. 557.
[EQ]"Sense-Organs and Perception of Fishes:" Journal of Marine Biological Association, New Series, vol. i. No. 3, p. 225.
[ER]Nature, vol. xlii. p. 201.
[ES]Nature, vol. xxxvi. p. 273.
[ET]Journal of Marine Biological Association, New Series, vol. i. No. 3, p. 235.
[EU]Mr. S. Klein mentions a similar fact in connection with Bombyx quercus (Nature, vol. xxxv. p. 282).
[EV]Journal of Marine Biological Association, New Series, vol. i. No. 2, p. 211.
[EW]A friend of mine informs me that his limit is about 17,500 per second, 20,000 being quite inaudible.
[EX]Journal of Marine Biological Association, New Series, vol. i. No. 3, p. 251.
[EY]Of course, anglers will say that what may be true for pollack and other coarse and vulgar sea-fish does not apply to King Salmon or Prince Trout.
[EZ]"Senses of Animals," p. 117.
[FA]See a very interesting and lucid paper by Professor Crum Brown, whose name is intimately connected with this subject, in Nature, vol. xl. p. 449.
[FB]It is interesting to note that in the blind-fish (Amblyopsis spelæus) the semicircular canals are, according to Wyman, unusually large.
[FC]The dampers must, of course, be lifted by depressing the loud pedal.
[FD]"Special Physiology," p. 636.
[FE]A band and not a line, because R. is unstable to the impact of a considerable range of light-vibrations.
[FF]Mr. Chattock has kindly supplied me with the following note:—
"Readings at the violet end were taken at the extremity of the lavender rays, at the point where the faint band of lavender light seemed to end off about half-way across the field of view (the cross-wires being invisible).
"At the red end the cross-wires were always visible, and were in each case set to the point where the top horizontal edge of the spectrum lost its definition.
"Other things equal, the 'red' readings should be more reliable than the violet, therefore, from the greater definiteness of the point observed, and the means of observing it. But against this has to be set off the fact that the extreme violet rays were spread out by the prism used more than eight times as much as the red rays.
"In any case, the wide differences observed in the 'red' readings are much greater than could have been due to misunderstanding or careless observation—as shown by setting the instrument to maximum and minimum readings, and noting the very obvious difference between them apparent to a normal eye. The same conclusion is rather borne out by the closer (average) agreement between the two eyes of the same individual than between those of different persons.
"The source of light was the central portion of an ordinary Argand burner."
[FG]The variations above indicated throw light on a fact to which Lord Rayleigh has directed attention. The yellow of the spectrum may be matched by a blending of spectral red and spectral green; but the proportions in which these spectral colours must be mixed differ for different individuals. The complementary colours for different individuals are also not precisely the same.
[FH]"Colour-Vision and Colour-Blindness," R. Brudenell Carter (Nature, vol. xlii. p. 56).
[FI]Journal of Marine Biological Association, New Series, vol. i. Nos. 2 and 3. His experiments with regard to the colour-sense in fishes gave, for the most part, negative results.
[FJ]We must remember how largely the antennæ are used when an insect is finding its way about. Watch, for example, a wasp as it climbs over your plate. If the antennæ be removed, it seems to stumble about blindly. The antennæ seem almost to take the place of eyes at close quarters.
[FK]"Senses of Animals," p. 194.
[FL]See Nature, vol. xli. p. 407.
[FM]Chap. x. p. 202.
[FN]The observations are not yet published, and I have to thank Lord Rayleigh for his courtesy in allowing me to make use of this fact.
[FO]Professor Langley finds that the maximum effect with a radiating
| source at | 170° C. | is at about | 5.0 | thousandths of a millimetre wave-length. |
| " | 100° C. | "" | 7.5 | """ |
| " | 0° C. | "" | 11.0 | """ |
We are sensitive to radiations from a body at 100° C. But when the temperature falls below the normal temperature of the body we are not sensitive to heat-vibrations, but to loss of heat from the surface exposed. The limit of sensibility to heat-vibrations, therefore, probably lies between 7.5 and 11 thousandths of a millimetre. I have taken about 9.25 as the limit.
[FP]I use this term in a broad sense, as the process involved in the formation of what I shall term constructs.
[FQ]And I may add it is not an easy matter to explain to those who have not considered such questions. It is a matter of the correlation of the testimony of the sense-organs. A boy stands before me. I go to him and touch him, and pass my hands downwards from head to foot. Then I stand a little way off and look at him. His image on my retina is inverted. But as I run my eye over him I direct my eye downwards to his feet and upwards to his head. I am not conscious that the stimuli are running upwards along the retinal image. Thus my eye-muscles and my other muscular and tactile sensations seem to tell me that he is one way upwards. The image on my retina tells me, though I am not conscious of the fact, that he is the other way upwards. But he cannot be both! The testimony of one sense has to give way. One standard or the other has to be adopted. Practically that of touch and the muscular sensations is unconsciously selected, and sight-sensations are habitually interpreted in terms of this standard. So long as the two are sufficiently accurately correlated, the practical requirements of the case are met. And it is well known that it is not difficult, with a little practice, to establish a new correlation. This is indeed done every day by the microscopist, for whom the images are all reversed by his instrument. He very soon learns, however, that to move the object, as seen, to the left, he must push it to the right. A new correlation is rapidly and correctly established.
[FR]I use this term because the word "percept" is used in different senses by different writers, e.g. by Mr. Mivart and Mr. Romanes.
[FS]"Let the perception be considered to be made up of x + y; x being the ego, or self, and y the object. The mind has the power of supplying its own - x, and so we get (through the imagination of the mind and the object) x + y - x, or y pure and simple" (Mivart, "On Truth," p. 135). Mr. Mivart devotes a whole section of this work to the defence of ordinary common-sense realism. The above assertion seems to contain the essence of his teaching in the matter.
[FT]If it be said that the object does exist independently of man, though not in the phenomenal guise under which we know it, I would reply—Not so; for it is to the existence under this phenomenal guise that we apply the word "object." In philosophical language, the existence, stripped of its phenomenal aspect, is called the Ding an sich. Its essential character is its independence of man; and hence its unknowability.
[FU]I avoid, for the present, the use of the terms "abstraction" and "abstract idea" because they are employed in different senses by different authors.
[FV]"Outlines of Psychology," p. 153.
[FW]Ibid. p. 339.
[FX]"Science of Thought," p. 453.
[FY]For compound or generic ideas "not consciously fixed and signed by means of an abstract name," Mr. Romanes ("Mental Evolution in Man," p. 36) has suggested the term "recept." In the photographic psychology which he adopts, the percept is an individual and particular photograph, the recept a generalized or composite photograph. "The word 'recept,'" he says, "is seen to be appropriate to the class of ideas in question, because, in receiving such ideas, the mind is passive." This, it will be observed, is in opposition to the teaching of this chapter, in which the activity of the mind in perception has been insisted on. Mr. Romanes's recepts answer in part to what I have termed constructs, which, as we have seen, are, as a rule, from the first general rather than particular, and in part to concepts reached through analysis. Mr. Romanes, for example, speaks of ideas of principles (e.g. the principle of the screw) and ideas of qualities (e.g. good-for-eating and not-good-for-eating) as recepts (p. 60). On the other hand, Mr. Mivart ("The Origin of Human Reason," p. 59; see also his work "On Truth") terms such generic affections "sensuous universals." It may be well to append Mr. Romanes's and Mr. Mivart's tabular statements.
| Mr. Romanes. | |||
| Ideas | { | General, abstract, or notional | = Concepts. |
| Complex, compound, or mixed | = Recepts, or generic ideas. | ||
| Simple, particular, or concrete | = Memories of percepts. | ||
| Mr. Mivart. | |||
| Ideas | { | General or true universals | = Concepts |
| Particular or individual | = Percepts. | ||
| Sensitive Cognitive Affections |  | Groups of actual experiences combined with sensuous reminiscences | = Sensuous universals, or recepts. |
| Groups of simply juxtaposed actual experiences | = Sense-perceptions, or sencepts. | ||
In Mr. Mivart's terminology, the representations of the lower group are "mental images" or "phantasmata." The term "consciousness" is by him restricted to the higher region of ideas, the term "consentience" being applied to the faculty by which cognitive affections are felt, unified, and grouped without consciousness. There is a difference in kind, according to Mr. Mivart, between "consentience" and "consciousness;" and the former could therefore never develop into the latter, nor the latter be evolved from the former. For this reason (because of the philosophy it is intended to carry with it) I shall not employ the word "consentience," which would otherwise be a useful term.
[FZ]We do not speak of the filling in the complement of a percept (the construction of the object at the bidding of a simple impression) as a matter of conscious inference. I do not consciously infer that yonder moss-rose is scented. Scent is an integral part of the construct. From the appearance of the rose, I may, however, infer that a rose-chafer has disturbed its petals. The complement of the percept, if inferred at all, is unconsciously inferred.
[GA]"Outlines of Psychology," p. 392.
[GB]"Outlines of Psychology," p. 414.
[GC]Mr. Romanes adopts a different use of the terms "reason" and "rational," to which allusion will be made in the next chapter.
[GD]"Chapters on Animals," p. 9.
[GE]Or perhaps we may say, in the language of analogy, that when the germinal psychoplasm of some dim form of organic memory is fertilized by the union therewith of the more active male element of discrimination, a process of segmentation of the psychoplasm sets in by which, in process of differentiation, the tissues and organs of the mind are eventually developed.
[GF]Nature, vol. xxxviii. p. 257.
[GG]For examples, see Romanes's "Animal Intelligence," p. 455.
[GH]I use the word "arbitrary" in the sense that they form no part of the normal construct such as would be formed by the animal.
[GI]"The Senses of Animals," p. 277.
[GJ]As I understand the observations here tabulated, the twelve cards lay always within Van's reach and sight. An ordinary untrained dog would have taken no notice of them. But Van, when he wanted food or tea, went and fetched the appropriate card, and got what he wanted in exchange. In twelve days he only made two mistakes, bringing "Nought" once and "Door" once.
[GK]"Mental Evolution in Man," p. 27.
[GL]"Intelligence of Animals," p. 121.
[GM]Mr. Romanes also says ("Mental Evolution in Animals," p. 235), "This abstract idea of ownership is well developed in many if not in most dogs." By an abstract idea of ownership I understand a conception of ownership which, to modify Mr. Romanes's phrase, is quite apart from any objects or persons of which such ownership happens to be characteristic. Even if we believe that a dog can regard this or that man as his owner, or this or that object as his master's property, still even this seems to me a very different thing from his possessing an abstract idea of ownership.
[GN]Doubt has recently been thrown on this fact. Mr. Bateson has shown that some fishes do not hear well, and has suggested that the carp may be attracted by seeing people come to the edge of the pond.
[GO]Journal of Marine Biological Association, New Series, vol. i. No. 2, p. 214. I should not myself have used the word "explanation."
[GP]Ibid. vol. i. No. 3, p. 240.
[GQ]I have to thank this gentleman for a most interesting account of the intelligence of his favourite bird.
[GR]Professor Max Müller suggests to me that perhaps the ants were frightened.
[GS]"Mental Evolution in Animals," p. 82.
[GT]Ibid. p. 48.
[GU]These fall under the "practical intelligence" of Mr. Mivart. All their intelligent activities, in his view, are performed by the exercise of merely sensitive faculties, through their "consentience." I agree to so large an extent with Mr. Mivart in his estimate of animal intelligence, and in his psychological treatment, that I the more regret our wide divergence when we come to the philosophy of the subject. I am with him in believing that conception and perception, in the sense he uses the words, are beyond the reach of the brute. But I see no reason to suppose that these higher faculties differ in kind from the lower faculties possessed by animals. They differ generically, but not in kind. I believe that, through the aid of language, the higher faculties have been developed and evolved from the lower faculties. Here, therefore, I have to part company from Mr. Mivart.
[GV]Romanes, "Animal Intelligence," p. 401.
[GW]"Animal Intelligence," p. 465.
[GX]"Animal Intelligence," p. 430; and Nature, vol. xix. p. 409.
[GY]"Animal Intelligence," p. 497.
[GZ]Mr. Romanes regards it as, in the case of the capuchin, a recept. But when he speaks of a generic idea of causation, and generic ideas of principles, and of qualities as recepts, I find it exceedingly difficult to follow him. They seem to me to be concepts supposed to be formed in the absence of language.
[HA]Page 54.
[HB]Vol. xx. p. 96.
[HC]Nature, vol. xxi. p. 34.
[HD]Romanes, "Animal Intelligence," p. 17: Definition of reason.
[HE]"Mental Evolution in Animals," p. 318.
[HF]"Lessons from Nature," pp. 226, 227.
[HG]"Physiological Æsthetics:" chapter on "Pleasure and Pain."
[HH]All of these, at any rate, satisfy Mr. Herbert Spencer's definition. Pleasure he describes as a feeling which we seek to bring into consciousness and retain there; pain, as a feeling which we seek to get out of consciousness and keep out.
[HI]"Types of Ethical Theory," vol. ii. p. 350.
[HJ]Such consciousness of activity is probably associated with the innervation of afferent, not efferent, nerves.
[HK]Journal of Marine Biological Association, New Series, vol. i. No. 2, pp. 216, 217.
[HL]"Outlines of Psychology," p. 481.
[HM]Ibid. p. 494.
[HN]Page 70.
[HO]Page 104.
[HP]Nature, vol. xxxvii. p. 619.
[HQ]Vol. i. p. 310, under date 1876.
[HR]"Mental Evolution in Animals," p. 318.
[HS]"Descent of Man," pt. i. chap. iii.
[HT]Miss Nellie Maclagan describes how her Newfoundland similarly took a roll to a hungry pauper-friend (Nature, vol. xxviii. p. 150). Mr. Duncan Stewart gives (Nature, vol. xxviii. p. 31) the case of a cat who used frequently to provide her blind mother with food. Sir Harry Lumsden states that during the cold autumn of 1878 some tame partridges in Aberdeenshire brought two wild coveys to be fed near the doorstep of the house. And a case has been communicated to me by Miss Agnes Tanner, of Clifton, of a thrush that pulled up worms on the lawn for a lame companion.
[HU]"Animal Intelligence," p. 440.
[HV]"Animal Intelligence," p. 442.
[HW]Ibid. p. 444.
[HX]Ibid. p. 451.
[HY]"Animal Intelligence," p. 387.
[HZ]"Animal Intelligence," p. 486.
[IA]Ibid. p. 141.
[IB]"Animal Intelligence," p. 443.
[IC]Mr. Alexander Mackennal, vol. xxi. p. 397.
[ID]"Descent of Man," pt. i. chap. iii., quoted from Brehm's "Thierleben."
[IE]Nature, vol. xxviii. p. 32.
[IF]"Descent of Man," quoted by Romanes, p. 445.
[IG]Nature, vol. xl. p. 327.
[IH]Another example of beauty which can hardly be said to have been evolved for beauty's sake is to be seen in birds' eggs. Mr. Henry Seebohm regards the bright colours of some birds' eggs as a difficulty in the way of the current interpretation of organic nature. "Few eggs," he says (Nature, vol. xxxv. p. 237), "are more gorgeously coloured [than those of the guillemot], and no eggs exhibit such a variety of colour. [They are sometimes of a bluish green, marbled or blotched with full brown or black; sometimes white streaked with brown; sometimes pale green or almost white with only the ghosts of blotches and streaks; and sometimes the reddish brown extends so as to form the ground-tint which is blotched with deeper brown.] It is impossible to suppose that protective selection can have produced colours so conspicuous on the white ledges of chalk cliffs; and sexual selection must have been equally powerless. It would be too ludicrous a suggestion to suppose that a cock guillemot fell in love with a plain-coloured hen because he remembered that last season she laid a gay-coloured egg."
If we connect colour with metabolic changes, its occurrence in association with the products of the highly vascular oviduct will not be surprising. Some guidance is, however, on the principles advocated in Chapter VI., required to maintain a standard of coloration. In many cases such guidance is found in protective selection, as in the plover's eggs in our frontispiece. In the guillemot's egg such protective selection seems to be absent, and, as Mr. Seebohm himself says, "no eggs exhibit such a variety of colour."
In our present connection, however, the point to be noticed is that many eggs are undoubtedly beautiful. But they cannot have been in any way selected for the sake of their beauty.
[II]"Outlines of Psychology," p. 537.
[IJ]I should add, "or as conceptual thought."
[IK]This paragraph is quoted from the author's "Springs of Conduct," p. 263.
[IL]Page 347.
[IM]I have said nothing about the emotions of invertebrates, because I have nothing special to say. They have, no doubt, emotions analogous to fear, anger, and so on. But it is difficult to interpret their actions. The "angry" wasp is, perhaps, a good deal more frightened than furious. Sir John Lubbock's interesting experiments seem to show that ants have what is termed the instinct of play. But this admirable observer has rendered it probable that sympathy and affection in ants and bees have been somewhat exaggerated.
[IN]I use the term "incomplete," and not "imperfect," because Mr. Romanes, in his admirable discussion of the subject, applies the term "imperfect instinct" to cases where the instinct is not perfectly adapted to the end in view (see "Mental Evolution in Animals," p. 167).
[IO]Macmillan's Magazine, February, 1873. Professor Eimer, in his "Organic Evolution" (English translation, p. 245), narrates similar experiences.
[IP]Mr. W. Larden states, in Nature (vol. xlii.), that his brother extracted, from the oviduct of a Vivora de la Cruz snake in the West Indies, two young snakelets six inches long. Both, though thus from their mother's oviduct untimely ripped, threatened to strike, and made the burring noise with the tail, characteristic of the snake.
[IQ]Dr. McCook confirms the observation that the clearings are kept clean, that the ant-rice alone is permitted to grow on them, and that the produce of this crop is carefully harvested; but he thinks that the ant-rice sows itself, and is not actually planted by the ants (see Sir John Lubbock's "Scientific Lectures," 2nd edit., p. 112).
[IR]The experiments, both of Sir John Lubbock and Mr. Romanes, show that the homing instinct of bees is largely the result of individual observation. Taken to the seashore at no great distance from the hive, where the objects around them, however, were unfamiliar (since the seashore is not the place where flowers and nectar are to be found), the bees were nonplussed and lost their way. Similarly, the migration of birds "is now," according to Mr. Wallace, "well ascertained to be effected by means of vision, long flights being made on bright moonlight nights, when the birds fly very high, while on cloudy nights they fly low, and then often lose their way" ("Darwinism," p. 442). This, of course, does not explain the migratory instinct—the internal prompting to migrate—but it indicates that the carrying out of the migratory impulse is, in part at least, intelligent.
[IS]"Animal Intelligence," p. 59.
[IT]The American expression, "I guess," is often far truer to fact than its English equivalent, "I think."
[IU]"Mental Evolution in Animals," pp. 73, 74.
[IV]"Mental Evolution in Animals," p. 177.
[IW]Nature, vol. xxviii. p. 271, quoted in "Mental Evolution in Animals," footnote, p. 196.
[IX]"Organic Evolution," pp. 223, 224.
[IY]Ibid. p. 263.
[IZ]Ibid. p. 303.
[JA]Ibid. p. 258.
[JB]Ibid. p. 279.
[JC]Ibid. p. 276.
[JD]"Organic Evolution," p. 298. The late G. H. Lewes held somewhat similar views.
[JE]See Mr. John Hancock, Natural History Transactions, Northumberland, Durham, and Newcastle-on-Tyne, vol. viii. (1886); and Nature, vol. xxxiii. p. 519.
[JF]Weismann, "On Heredity," p. 91.
[JG]M. Fabre, as interpreted by Sir John Lubbock, "Scientific Lectures," 2nd edit., p. 45.
[JH]In further illustration of the fact that purposiveness and complex adaptation of activities is no criterion of present or past direction by intelligence, we may draw attention to the action of the leucocytes, or white blood-corpuscles. Metchnikoff found that in the water-flea (Daphnia), affected by spores of Monospora bicuspidata, a kind of yeast which passes from the intestinal canal into the body-cavity, the leucocytes attacked and devoured the conidia. If a conidium were too much for one cell, a plasmodium, or compound giant-cell, was formed to repel the invader. The same thing occurs in anthrax, the bacilli being attacked and devoured by the leucocytes. "If we summarize," says Mr. Bland Sutton ("General Pathology," pp. 127, 128), "the story of inflammation as we read it zoologically, it should be likened to a battle. The leucocytes are the defending army, their roads and lines of communication the blood-vessels. Every composite organism maintains a certain proportion of leucocytes as representing its standing army. When the body is invaded by bacilli, bacteria, micrococci, chemical or other irritants, information of the aggression is telegraphed by means of the vaso-motor nerves, and leucocytes rush to the attack; reinforcements and recruits are quickly formed to increase the standing army, sometimes twenty, thirty, or forty times the normal standard. In the conflict, cells die and often are eaten by their companions; frequently the slaughter is so great that the tissue becomes burdened by the dead bodies of the soldiers in the form of pus, the activity of the cell being testified by the fact that its protoplasm often contains bacilli, etc., in various stages of destruction. These dead cells, like the corpses of soldiers who fall in battle, later become hurtful to the organism they were in their lifetime anxious to protect from harm, for they are fertile sources of septicæmia and pyæmia—the pestilence and scourge so much dreaded by operative surgeons." Now, if the leucocytes were separate organisms, whose habits were being described, some might suppose that they were actuated by intelligence, individual or inherited. But in this case the activities are purely physiological. The marshalling of the cells during the growth of tissue (e.g. the antler of a stag before described) is of like import. And Dr. Verworn has shown that when a (presumably weak) electric current is passed through a drop of water containing protozoa, they will, when the current is closed, flock towards the negative pole, and when the current is opened will travel towards the positive pole. The implication of all this is that vital phenomena may be intensely purposive, and yet afford no evidence or indication of the present or ancestral play of intelligence.
[JI]"Origin of Species," p. 230.
[JJ]See Appendix to Mr. Romanes's "Mental Evolution in Animals," p. 361.
[JK]"Organic Evolution," p. 227.
[JL]Ibid. p. 228.
[JM]"Colours of Animals," p. 180.
[JN]Wallace's "Darwinism," p. 109.
[JO]"Mental Evolution in Animals," p. 244.
[JP]"Descent of Man," pt. ii. chap. xiii.
[JQ]George W. and Elizabeth G. Peckham, "Occasional Papers of the Natural History of Wisconsin," vol. i. (1889), p. 37.
[JR]"Mental Evolution in Animals," p. 226.
[JS]"Darwinism," p. 76, from Nature, vol. xxxi. p. 533.
[JT]"Contributions," etc., p. 222.
[JU]"Mental Evolution in Animals," p. 222.
[JV]"On Sheep," p. 404.
[JW]In the sense in which I have used the word; not as he uses it himself.
[JX]"Moral Order and Progress."
[JY]"Contributions to the Theory of Natural Selection," p. 365.
[JZ]I consider that an apology is needed for the coinage of this and of two or three other words, such as "construct," "isolate," and "predominant." I can only say that in each case I endeavoured to avoid them, but found that I could not make my meaning clear, or bring out the point I wished to emphasize without them.
[KA]"Science of Thought," pp. 286, 287.
[KB]"Science of Thought," p. 279.
[KC]I use "substance" here in its philosophical sense.
[KD]Quoted in Professor Veitch's "Hamilton," p. 77.
[KE]T. M. Herbert, "The Realistic Assumptions of Modern Science Examined," 2nd edit., p. 123.
[KF]"Science of Thought," p. 571.
[KG]Strictly speaking, of the brain; but since the brain has no organic independence of the body, it is best here to focus attention on the unity of the organism.
[KH]I ought not to pass over without notice the "psychological scale" which Mr. Romanes introduces in a table prefixed to "Mental Evolution in Animals." It would be unjust to criticize this too closely, for it is admittedly provisional and tentative. If such a scheme is to be framed, I would suggest that the various phyla of the animal kingdom be kept distinct. I question, however, whether any one can produce a scheme which any other independent observer will thoroughly endorse. And I am inclined to think that the wisest plan is to tabulate the kinetic manifestations which we can actually observe rather than the metakineses of which we can have no independent knowledge.
[KI]Contemporary Review, July, 1886. See Clifford's "Lectures and Essays," vol. i. pp. 72 and 248; vol. ii. p. 67.
[KJ]Contemporary Review, July, 1886.
[KK]"Darwinism," p. 467.
[KL]In both cases, the question to which an answer is suggested is not—What variations will arise? but—What variations will survive?
[KM]"Darwinism," p. 293. It is strange that Mr. Wallace did not apply this view to the mathematical and artistic faculties discussed in his last chapter. It is true that such application tends to undermine the argument there developed. But Mr. Wallace is far too great and conscientious a thinker to be influenced by such a consideration.
[KN]If elimination of the unintellectual (not necessarily of the unintelligent) may be excluded, and if the unintellectual increase by natural generation more rapidly than the intellectual, the general level of intellectuality must, on Professor Weismann's principles, be steadily falling.
[KO]It may also, in part, be due to "organic combination."