Thomas Henry Huxley; A Sketch Of His Life And Work Part 7

Falkenstein has given a detailed description of a gorilla which was remarkable for his delicacy in eating.

"He would take a cup or gla.s.s with the greatest care, using both hands to carry it to his mouth, and setting it down so carefully that I do not remember having lost a single piece of crockery through him, though we had never tried to teach him the use of such vessels, wis.h.i.+ng to bring him to Europe as nearly in his natural condition as possible."

These and a mult.i.tude of similar observations which have been made since Huxley wrote are typical of the increase of our knowledge on the habits and capacities of the anthropoid apes. They all serve to show that in them the instinct for experimental investigation of everything with which they are surrounded, and their imitative faculties are peculiarly great. The importance of this, from the point of view of Huxley's argument, is great. The difference between the instincts of the lower animals and the intelligence of man is that instincts are to a large extent fixed and mechanical. The proper performance of an instinct demands the presence of exactly the right external conditions for its accomplishment. In the absence of these conditions, the call to perform the instinctive action is equally great, and results in useless performances. In many of the higher animals these elaborate instincts are more general in their character, and are supplemented by a considerable but varying apt.i.tude for modification of instinctive action to suit varieties of surrounding circ.u.mstances. As this intelligence becomes more and more developed, the blind, mechanical instinct becomes weaker. A large number of instances might be given of such instincts modified by dawning intelligence. The chief factors in producing the change are, as has been shewn by Professor Groos, the possession of a general instinct to imitate and to experiment, and the existence of a period of youth in which the young creature may practise these instincts, and so prepare itself for the more serious purposes of adult life. The anthropoid apes seem to possess these experimental instincts to an extent much greater than that observed in any other cla.s.s of animals, and, as they have a long period of youth, they have the opportunity of putting them into practice to the fullest possible extent.

From the natural history of the anthropoid apes, Huxley pa.s.sed to consideration of their relation to man, prefacing his observations with a pa.s.sage defending the utility of the enquiry, a pa.s.sage necessary enough in these days of prejudice, but now chiefly with historical interest:

"It will be admitted that some knowledge of man's position in the animate world is an indispensable preliminary to the proper understanding of his relations to the universe; and this again resolves itself in the long run into an enquiry into the nature and the closeness of the ties which connect him with those singular creatures whose history has been sketched in the preceding pages.

"The importance of such an enquiry is, indeed, intuitively manifest. Brought face to face with these blurred copies of himself, the least thoughtful of men is conscious of a certain shock; due perhaps not so much to disgust at the aspect of what looks like an insulting caricature, as to the awakening of a sudden and profound mistrust of time-honoured theories and strongly rooted prejudices regarding his own position in nature, and his relations to the underworld of life; while that which remains a dim suspicion for the unthinking, becomes a vast argument, fraught with the deepest consequences, for all who are acquainted with the recent progress of the anatomical and physiological sciences."

Huxley then proceeded to elaborate the argument from development for the essential ident.i.ty of man and the apes. This argument has now become more or less familiar to us all, as it has gained additional support from recent extension of embryological knowledge, and as it has been used in every work on evolution since Huxley first laid stress on it. The adult forms of animals are much more complex than their embryonic stages, and the series of changes pa.s.sed through in attaining the adult condition make up the embryological history of the animal. Huxley took the embryology of the dog as an example of the process in the higher animals generally, and as it had been worked out in detail by a set of investigators. The dog, like all vertebrate animals, begins its existence as an egg; and this body is just as much an egg as that of a fowl, although, in the case of the dog, there is not the acc.u.mulation of nutritive material which bloats the egg of the hen into its enormous size. Since Huxley wrote, it has been shewn clearly that among the mammalian animals there has been a gradual reduction in the size of the egg. The ancestors of the mammals laid large eggs, like those of birds or reptiles; and there still exist two strange mammalian creatures, the Ornithorhynchus and Echidna of Australia, which lay large, reptilian-like eggs. The ancestors of most living mammalia acquired the habit of retaining the eggs within the body until they were hatched; and, as a result of this, certain structures which grow out from the embryo while it is still within the egg and become applied to the inner wall of the porous sh.e.l.l for the purpose of obtaining air, got their supply of oxygen, not from the outer air, but from the blood-vessels of the maternal tissues. When this connection (called the placenta) between embryo and mother through the egg-sh.e.l.l became more perfect, not only oxygen but food-material was obtained from the blood-vessels of the mother; and, in consequence, it became unnecessary for the eggs to be provided with a large supply of food-yolk. Among existing marsupial animals, which, on the whole, represent a lower type of mammalian structure than ordinary mammals, there is more food-yolk than in ordinary mammals, and less food-yolk than in the two egg-laying mammals. In the ordinary mammals, such as the rabbit, dog, monkey, and man, there is practically no yolk whatever deposited in the egg; the egg is of minute size, and the embryo obtains most of its food from the maternal blood.

The small egg of the mammal divides into a number of cells, which form a hollow sphere; on the upper surface of this the development of organs begins with the formation of a depression which indicates the future middle line of the animal, and is, in fact, the beginning of the nervous system. Under this is formed a straight rod of gelatinous material, the foundation of the vertebral column, and the body of the embryo is gradually pinched off from the surface of the hollow sphere.

After tracing the details of this process, Huxley proceeded as follows:

"The history of the development of any other vertebrate animal, lizard, snake, frog or fish, tells the same story. There is always, to begin with, an egg, having the same essential structure as that of the dog; the yolk of that egg always undergoes division, or segmentation, as it is often called; the ultimate products of that segmentation const.i.tute the building materials for the body of the young animal; and this is built up round a primitive groove, in the floor of which a notochord is developed. Furthermore, there is a period in which the young of all these animals resemble one another, not merely in outward form, but in all essentials of structure, so closely, that the differences between them are inconsiderable, while in their subsequent course they diverge more and more widely from one another. And it is a general law, that, the more closely any animals resemble one another in adult structure, the longer and the more intimately do their embryos resemble one another; so that, for example, the embryos of a snake and of a lizard remain like one another longer than do those of a snake and of a bird; and the embryos of a dog and of a cat remain like one another for a far longer period than do those of a dog and a bird; or of a dog and an opossum; or even than those of a dog and a monkey."

This general rule, that the longer the paths of embryonic development of two animals keep identical the more nearly the two animals are related, when Huxley wrote, was founded on a much smaller number of facts than now are known. Since 1860 an enormous bulk of embryological investigation has been published, and the total result has been to confirm Huxley's position in the fullest possible way. A certain number of exceptions have been found, but these exceptions are so obviously special adaptations to special circ.u.mstances that their existence only makes the general truth of the proposition more clear.

The most common kind of exception occurs when two closely related animals live under very different conditions. For instance, many marine animals have close allies that in comparatively recent times have taken to live in fresh water. The conditions of life in fresh water are very different, especially for delicate creatures susceptible to rapid changes of temperature, or unable to withstand strong currents. Thus most of the allies of the fresh-water crayfish, which live in the sea, lay eggs from which there are soon hatched minute, almost transparent larvae, exceedingly unlike the adult. In the comparatively equable temperature of sea-water, and in the usual absence of strong currents, these small larvae, as Huxley shewed later in his volume on the _Crayfish_, live a free life, obtaining their own food, and by a series of slow transformations gradually acquire the adult form. In fresh water, however, the delicate larvae would be unable to live, and the mode of development is different. The series of slow transformations is condensed, and takes place almost entirely inside the egg-sh.e.l.l; so that, when hatching occurs, the young crayfish is exceedingly like the adult. Apart from such special cases, it is true that the study of development affords a clear test of closeness of structural affinity.

Huxley then proceeds to discuss the development of man.

"Is he something apart? Does he originate in a totally different way from dog, bird, frog, and fish, thus justifying those who a.s.sert him to have no place in nature, and no real affinity with the lower world of animal life? Or does he originate in a similar germ, pa.s.s through the same slow and gradually progressive modifications, depend on the same contrivances for protection and nutrition, and finally enter the world by the help of the same mechanism? The reply is not doubtful for a moment, and has not been doubtful any time these thirty years. Without question, the mode of origin, and the early stages of the development of man are identical with those of animals immediately below him in the scale; without doubt, in these respects, he is far nearer the apes than the apes are to the dog."

Then, on lines with which, by continuous repet.i.tion and expansion by authors subsequent to him, we have now become familiar, Huxley compared, stage by stage, the development of man with that of other animals, and shewed, first, its essential similarity, and then that in every case where it departed from the development of the dog it resembled more closely the development of the ape. He went on to review the anatomy of man:

"Thus, identical in the physical processes by which he originates,--identical, in the early stages of his formation--identical in the mode of his nutrition before and after birth, with the animals which lie immediately below him in the scale,--Man, if his adult and perfect structure be compared with theirs exhibits, as might be expected, a marvellous likeness of organisation. He resembles them as they resemble one another--he differs from, them as they differ from one another.

And, though these differences cannot be weighed and measured, their value may be readily estimated; the scale or standard of judgment, touching that value, being afforded and expressed by the system of cla.s.sification of animals now current among zoologists."

Having explained the general system of zoological cla.s.sification, he tried to dispel preliminary prejudice by inducing his readers or bearers to take an outside view of themselves.

"Let us endeavour for a moment to disconnect our thinking selves from the mask of humanity; let us imagine ourselves scientific Saturnians, if you will, fairly acquainted with such animals as now inhabit the earth, and employed in discussing the relations they bear to a new and singular 'erect and featherless biped,'

which some enterprising traveller, overcoming the difficulties of s.p.a.ce and gravitation, has brought from that distant planet for our inspection, well preserved, may be, in a cask of rum. We should all, at once, agree upon placing him among the mammalian vertebrates; and his lower jaw, his molars, and his brain, would leave no room for doubting the systematic position of the new genus among those mammals whose young are nourished during gestation by means of a placenta, or what are called the placental mammals.

"Further, the most superficial study would at once convince us that, among the orders of placental mammals, neither the whales, nor the hoofed creatures, nor the sloths and ant-eaters, nor the carnivorous cats, dogs, and bears, still less the rodent rats and rabbits, or the insectivorous moles and hedgehogs, or the bats, could claim our _h.o.m.o_ as one of themselves.

"There would remain, then, but one order for comparison, that of the apes (using that word in its broadest sense), and the question for discussion would narrow itself to this--Is Man so different from any of these apes that he must form an order by himself? Or does he differ less from them than they differ from one another,--and hence must take his place in the same order with them?

"Being happily free from all real or imaginary personal interest in the results of the enquiry thus set afoot, we should proceed to weigh the arguments on one side and on the other, with as much judicial calmness as if the question related to a new opossum.

We should endeavour to ascertain, without seeking either to magnify or diminish them, all the characters by which our new mammal differed from the apes; and if we found that these were of less structural value than those which distinguish certain members of the ape order from others universally admitted to be of the same order, we should undoubtedly place the newly discovered tellurian genus with them."

In pursuit of this method, and taking the gorilla as the type for immediate comparison with man, he pa.s.sed in review the various anatomical structures, shewing that in every case man did not differ more from the gorilla than that differed from other anthropoids. We shall take a few examples of his method and results, reminding our readers, however, that Huxley carried his comparisons into every important part of the anatomical structure.

There is no part of the skeleton so characteristically human as the bones which form the pelvis, or bony girdle of the hips. The expanded haunch-bones form a basin-like structure which affords support to the soft internal viscera during the habitually upright position, and gives s.p.a.ce for the attachment of the very large muscles which help man to a.s.sume and support that att.i.tude. In the gorilla this region differs considerably from that in man. The haunch-bones are narrower and much shallower, so that they do not form so convenient a supporting basin; they have much less surface for the attachment of muscles. The gibbon, however, differs more vastly from the gorilla than that differs from man. The haunch-bones are flat and narrow, and totally devoid of any basin-like formation; the pa.s.sage through the pelvis is long and narrow, and the ischia have outwardly curved prominences, which, in life, are coated by callosities on which the animal habitually rests, and which are coa.r.s.e, corn-like patches of skin wholly absent in the gorilla, in the chimpanzee, in the orang, and in man.

In the characters of the hands, the feet, and the brain, certain real or supposed structural distinctions between man and the apes had been relied upon.

"Man has been defined as the only animal possessed of two hands terminating his fore-limbs, and of two feet terminating his hind-limbs, while it has been said that all the apes possess four hands; and he has been affirmed to differ fundamentally from all the apes in the characters of his brain, which alone, it has been strangely a.s.serted and rea.s.serted, exhibits the structures known to anatomists as the posterior lobe, the posterior cornu of the lateral ventricle, and the hippocampus minor.

"That the former proposition should have gained general acceptance is not surprising--indeed, at first sight, appearances are much in its favour; but, as for the second, one can only admire the surpa.s.sing courage of its enunciator, seeing that it is an innovation which is not only opposed to generally and justly accepted doctrines, but which is directly negatived by the testimony of all original enquirers who have specially investigated the matter; and that it has neither been, nor can be, supported by a single anatomical preparation. It would, in fact, be unworthy of serious refutation except for the general and natural belief that deliberate and reiterated a.s.sertions must have some foundation."

The last remarks referred, of course, to the statements of Owen, which had made a great impression at the time and the result of which still lingers in some of the worse-informed treatises attacking evolution.

Huxley gave a lucid account of the general structure and arrangement of the brain in the vertebrate series, explaining the well-known fact that from fish up to man the general ground-plan of the brain is identical, but that there is a progressive increase in the complexity and in the size of some parts compared with others. Next, he showed that, so far from its being possible to erect any barrier in the structure of the brain between man and the apes, there exists among the mammals an almost complete series of gradations from brains a little higher than that of the rabbit to brains a little lower than that of man. He laid great stress on

"the remarkable circ.u.mstance that though, so far as our present knowledge extends, there _is_ one structural break in the series of forms of simian brains, this hiatus does not lie between man and the man-like apes, but between the lower and the lowest simians; or, in other words, between the old-and new-world apes and monkeys, and the lemurs. Every lemur which has yet been examined, in fact, has its cerebellum partially visible from above, and its posterior lobe, with the contained posterior cornu and hippocampus minor, more or less rudimentary. Every marmoset, American monkey, old-world monkey, baboon, or man-like ape, on the contrary, has its cerebellum entirely hidden, posteriorly, by the cerebral lobes, and possesses a large posterior cornu, with a well-developed hippocampus minor." ... "So far from the posterior lobe, the posterior cornu, and the hippocampus minor being structures peculiar to, and characteristic of man, as they have over and over again been a.s.serted to be, even after the publication of the clearest demonstration of the reverse, it is precisely these structures which are the most marked cerebral characters common to man with the apes. They are among the most distinctly simian peculiarities which the human organism exhibits." ... "Man differs from the chimpanzee or the orang, so far as cerebral structure goes, less than these do from the monkeys, and the difference between the brains of the chimpanzee and of man is almost insignificant, when compared with that between the chimpanzee brain and that of a lemur."

Although Huxley found no structural differences between the brains of man and of anthropoid apes, he was careful to lay great stress on the important difference in size and weight. A full-grown gorilla is nearly twice as heavy as a European woman, and yet the heaviest known gorilla brain probably does not exceed twenty ounces in weight, while healthy adult human brains probably never weigh less than thirty-one or thirty-two ounces. This difference is not of systematic importance; for cranial capacities shew that relatively and absolutely there is a greater difference in brain-weight between the lowest and highest human beings than there is between the highest ape and the lowest human being.

In dealing with the suggestion that man differs from the apes in being bimanous, while the apes are quadrumanous, Huxley first explained and discussed what the exact differences between hands and feet are. He shewed that in man the foot is absolutely distinguished from the hand by three structural points, although the two organs are similar in general ground-plan. These structural points are:

1. The arrangement of the tarsal bones.

2. The possession of a short flexor and short extensor muscle of the digits.

3. The possession of a muscle named _peronaeus longus_.

Then he described the foot of the gorilla, and shewed that although it was superficially hand-like, it possessed all the structural characters that distinguish a foot from a hand. Tracing the structure of the foot downwards through the series of anthropoids and monkeys, he established clearly that, while important differences existed in nearly every single creature, the differences between the gorilla and man were not greater than those between the gorilla and other anthropoids, and less than between the gorilla and lower monkeys.

This wonderful series of lectures ranks very high among the important works of Huxley. It is true that a considerable proportion of the work was not absolutely original, but it had all been specially verified by him. It was a task undertaken with the greatest courage, and with a care equal to the courage; and it settled conclusively for all time the impossibility of making between man and the anthropoids any anatomical barriers greater than those which exist between the different although closely related members of any of the other family groups in the animal kingdom. The advance of knowledge has only added to the details of Huxley's argument; it has not made any reconstruction of it necessary. A writer on the same subject to-day would to all certainty make use of the same general methods. The chief differences, perhaps, that would be made are two: First, greater stress would be laid on the distinction, first made by Huxley himself, between intermediate and linear types. (See p. 87). To use the popular phrase, a great deal of water has pa.s.sed under the bridges since the separation of man from the ape-like progenitors common to him and to the existing anthropoids. It has already been pointed out that the gradual extinction of lower races of man is widening the apparent gap between existing man and existing apes; and evidence acc.u.mulates that many still more primitive and more ape-like races of man than the lowest existing savages have disappeared from the surface of the earth. Moreover, we know that existing anthropoids are the degenerate and scattered remnants of what was once a much more widely spread and more important group. We have some reason for believing the contrary, and no reason for believing that the surviving anthropoids represent the most man-like apes that have lived.

The second great point in which a modern writer would amend Huxley's statement of the case is more purely anatomical. One result of Darwin's work has been that anatomists attend much more closely to the slight variations of anatomical structure to be found among individuals of the same species. A comparison between an individual human body and the body of an individual gorilla is not now considered sufficient. The comparison must be made between the results of dissection of a very large number of men and of a very large number of gorillas. The anatomy of a type is not the anatomy of an individual; it is a kind of central point around which there oscillate the variations presented by the individuals belonging to the type. So far as this newer method has been applied, it has been found that the variations of the gorilla type frequently, in the case of individual organs, overlap the variations of the human type, and that the structure of man differs from the structure of any anthropoid type only in that the abstract central point of its variations is slightly different from the abstract central point of the variations presented by individual orangs, gorillas, and chimpanzees.

CHAPTER X

SCIENCE AS A BRANCH OF EDUCATION

Science-Teaching Fifty Years Ago--Huxley's Insistence on Reform--Science Primers--Physiography--Elementary Physiology--_The Crayfish_--Manuals of Anatomy--Modern Microscopical Methods--Practical Work in Biological Teaching--Invention of the Type System--Science in Medical Education--Science and Culture.

Less than half a century ago, there was practically no generally diffused knowledge of even the elements of science and practically no provision for teaching it. Medical students, in the course of their professional education, received some small instruction in botany, chemistry, and physiology; in the greater universities of England and the Continent there were not in all a dozen professors.h.i.+ps of science apart from special branches of medicine; in the Scottish universities there were one or two dreamy chairs of "Natural and Civil History,"

the occupiers of which were supposed to dispense instruction in half a dozen sciences. There was no scientific teaching at the public schools; there were practically no books available for beginners in science, and even the idea of guides to laboratory work had not been invented. Huxley, addressing in 1854 a particularly select audience in St. Martin's Hall, London, spoke to them of the

"utter ignorance as to the simplest laws of their own animal life, which prevails among even the most highly educated persons in this country." "I am addressing," he said, "I imagine, an audience of cultivated persons; and yet I dare venture to a.s.sert that, with the exception of those of my hearers who may chance to have received a medical education, there is not one who could tell me what is the meaning and use of an act which he performs a score of times every minute, and whose suspension would involve his immediate death:--I mean the act of breathing--or who could state in precise terms why it is that a confined atmosphere is injurious to health."

The power to express the precise meaning of even a common physiological act is probably not yet possessed by all educated people: but no one can doubt that there is now a very generally diffused knowledge of and interest in the ordinary processes of living bodies. It is almost impossible for any of us to escape some amount of scientific education at school, at college, from lectures, or from books. Certainly those of us who have a natural inclination towards knowledge of that kind can hardly fail to have the opportunity of acquiring it. Every library abounds in elementary and advanced scientific books; every university and many schools have their lectures and laboratories for science, and there is scientific teaching involved in every educational curriculum. To attempt a complete account of how this radical change in the att.i.tude of the world to science has come about would be to attempt to write the history of European civilisation in the last half-century. A thousand causes have been contributory; but among these causes two have been of extraordinary importance--an idea and a man. The idea is the conception of organic evolution, and the man was Huxley. The idea of evolution clothed the dead bones of anatomy with a fair and living flesh, and the new body left the dusty corners of museums to pervade the world, arousing the attention and interest of all. A large part of the prodigious mental activities of Huxley was devoted to compelling the world to take an interest in biological science. Had his life-work been no more than this side of it, it would have been of commanding importance. A mere enumeration of the modes in which he a.s.sisted in arousing attention to science among all cla.s.ses would fill many pages.

Almost before he was settled in London, in the lecture from which we quoted at the beginning of this chapter he urged the "educational value of the natural history sciences." In 1869 in a speech in Liverpool; in 1870 at University College, London; in 1874 as his Rectorial address in the University of Aberdeen; in 1876 at the opening ceremonial of the Johns Hopkins University at Baltimore; in the same year at South Kensington; in 1877 in a separate essay; in 1881 in an address to the International Medical Congress: at these different times and addressing different and important audiences he continued to urge the absolute necessity of a knowledge of nature. A well-known and eloquent pa.s.sage from an address on "a liberal education" delivered to working men in 1868 contains the gist of his reiterated argument:

"Suppose it were perfectly certain that the life and fortune of every one of us would, one day or other, depend on his winning or losing a game of chess, don't you think that we should all consider it to be a primary duty to learn at least the names and the moves of the pieces; to have a notion of a gambit, and a keen eye for all the means of giving and getting out of check? Do you not think that we should look with a disapprobation amounting to scorn upon the father who allowed his son, or the state which allowed its members, to grow up without knowing a p.a.w.n from a knight?

Yet it is a very plain and elementary truth, that the life, the fortune, and the happiness of every one of us, and more or less of those who are connected with us, do depend upon our knowing something of the rules of a game infinitely more difficult and complicated than chess. It is a game which has been played for untold ages, every man and woman of us being one of the two players in a game of his or her own. The chess-board is the world, the pieces are the phenomena of the universe, the rules of the game are what we call the laws of nature. The player on the other side is hidden from us. We know that his play is always fair, just, and patient. But also we know, to our cost, that he never overlooks a mistake, or makes the smallest allowance for ignorance. To the man who plays well, the highest stakes are paid, with that sort of overflowing generosity with which the strong shows delight in strength, and one who plays ill is checkmated--without haste, but without remorse."

Huxley wished that this scientific education should begin at an early period of every child's training. In 1869 he wrote:

"Let every child be instructed in those general views of the phaenomena of nature for which we have no exact English name. The nearest approximation to a name for what I mean which we possess is physical geography; the Germans have a better, 'Erdkunde'