Thomas Henry Huxley

“ If any one assert that there are other orders of facts which enter into this question, but which are distinguished by being neither demonstrable nor discernible, all that can be replied is, that science is incompetent either to affirm or deny his proposition, confined, as she is, to the humble, if safe, region of observation and of logic. ”

“ Compare the bony frame-work, the muscles, the great vessels, the viscera, of man, the dog, and the rabbit, and the demonstration of a pervading unity of plan in all three is one of the triumphs of modern science. ”

“ The form of the human brain is well known. Its singular height, the width of the frontal lobe, whose anterior extremity, instead of narrowing to an acute point, is terminated by a surface whose extent corresponds to that of the frontal bone; the large angle which the two orbital fossæ form, the depression of the fissure of Sylvius, the richness and complications of the secondary convolutions, at once distinguish this brain from that of all the Primates. ”

“ In other words, if we place A, the European brain, B, the Bosjesman brain, and C, the orang brain, in a series, the differences between A and B, so far as they have been ascertained, are of the same nature as the chief of those between B and C.
The brains of the lowest races of mankind have been hardly at all examined; and it would be a matter of great interest to ascertain whether, in these races, there is any trace of the external perpendicular fissure, any diminution of the lobule of the marginal convolution, and any increase of the proportional size of the nerves to the cerebral mass. ”

“ The proof of his claim to independent parentage will not change the brutishness of man's lower nature; nor, except to those valet souls who cannot see greatness in their fellow because his father was a cobbler, will the demonstration of a pithecoid pedigree one whit diminish man's divine right of kingship over nature; nor lower the great and princely dignity of perfect manhood, which is an order of nobility, not inherited, but to be won by each of us, so far as he consciously seeks good and avoids evil, and puts the faculties with which he is endowed to their fittest use. ”

“ Nor can any impartial judge doubt that the roots, as it were, of those great faculties which confer on man his immeasurable superiority above all other animate things, are traceable far down into the animal world. The dog, the cat, and the parrot return love for our love, and hatred for our hatred. ”

“ In man, the brain presents an ascensive step in development, higher and more strongly marked than that by which the preceding sub-class was distinguished from the one below it. Not only do the cerebral hemispheres (figs. 5 & 6 A) overlap the olfactory lobes and cerebellum, but they extend in advance of the one, and further back than the other (fig. 6, C) . Their posterior development is so marked, that anatomists have assigned to that part the character of a third lobe ”

“ As the biological sciences have grown in breadth and in depth, and as successive generations of naturalists have succeeded in penetrating further and further into the arcana of nature, the questions—In what relation does the thinker and investigator stand to the objects of his inquiries? What is the tie which connects man with other animated and sentient beings?—have more and more forcibly pressed for a reply. ”

“ On the other hand, the students of physical science, discovering as complete a system of law and order in the microcosm as in the macrocosm, incessantly lighting upon new analogies and new identities between life as manifested by man, and life in other shapes,—have no less steadily gravitated towards the opposite opinion, and, as knowledge has advanced, have more. ”

“ The convoluted brain of man and the smooth brain of the marmoset resemble one another in the fourfold character of a rudimentary olfactory lobe, a posterior lobe, which completely covers the cerebellum, a well-marked fissure of Sylvius, and lastly, a posterior cornu to the lateral ventricle. These characters are met with in combination only in man and in the apes. ”

“ But, after all, it is the latter question which really interests science; and, therefore, it seems to me, that some service may be done by setting about the inquiry in a different way—by endeavouring, in fact, to answer the question—What is the value of the differences observed between man and the lower animals, as compared with the differences between the lower animals themselves? ”

“ In the orang, the same proportion obtains as in the new-born child or 1 : 2, a result which is certainly remarkable, and proves that, in this respect, the brain of the orang stands higher than that of the chimpanzee. The second point to which we would direct attention is, that in comparing the brain of man with that of animals, and especially in determining in what manner the cerebellum becomes covered we too exclusively attend to the posterior elongation of the cerebral hemispheres, while the varying size of the cerebellum itself ought to be taken into account. ”

“ Fortunately, M. Gratiolet has also particularly described and carefully figured this brain (which is that of the "Hottentot Venus;" who died in Paris, and had the honour of being anatomized by Cuvier) , and his remarks upon the subject are exceedingly important and instructive:—
"This woman, be it premised, was no idiot. Nevertheless, it may be observed, that the convolutions of her brain are relatively very little complicated. But what strikes one, at once, is the simplicity, the regular arrangement of the two convolutions which compose the superior stage of the frontal lobe. ”

“ Important or unimportant in its final results as it may be, however, there can be no doubt that the controversy as to the real position of man still exists; and I have therefore thought that it would be useful to contribute my mite towards the enrichment of the armoury upon which both sides must, in the long run, be dependent for their weapons, by endeavouring to arrange and put in order the facts of the case, so far as they consist of the only matters of which the anatomist and physiologist can take cognizance—I mean facts of discernible structure and of demonstrable function. ”

“ That there are a great number of points of similarity between ourselves and the lower animals, then, appears to be clearly admitted on all hands. It is, further, universally allowed that the Vertebrata resemble man more nearly than do any invertebrates; that among vertebrates the Mammalia, and of these the Quadrumana, approach him most closely. Lastly, I am aware of no dissentient voice to the proposition, that in the whole, the genera Troglodytes, Pithecus, and Hylobates, make the closest approximation to the human structure. ”

“ No one denies, I believe, that there are multitudes of analogies and affinities of structure and function connecting man with other living- beings. Man takes his origin in an ovum similar in form, in size, and in structure to that whence the dog or the rabbit arise. The physical process which determines the development of the embryo within that ovum; the successive stages of that development; the mode in which the human foetus is nourished within the maternal organism ”

“ Of the first brain he examined—that of a young female chimpanzee, seven or eight months old,—this eminently careful anatomist and physiologist says (under date of May 24, 1860) :—
"There is, very clearly, a posterior lobe, separated from the middle one by as deep a groove between the convolutions on the inner side of the hemispheres, as in man, and equally well marked off on the other side. ”

“ In the anthropoid apes the brain is smaller, as compared with the nerves which proceed from it, than in man.
2. In the anthropoid apes the cerebrum is smaller, relatively to the cerebellum, than in man.
3. In the anthropoid apes the sulci and gyri are generally less complex, and those of the two cerebral hemispheres are more symmetrical, than in man.
4. The hemispheres are more rounded and deeper in man than in the anthropoid apes, and the proportions of the lobes to one another are different. ”

“ If, as I shall endeavour to show, this question can be demonstrably answered in the affirmative;—if it can be proved beyond doubt, that whether we consider the skeleton, the muscles, the brain, or the other viscera, man is far less distant from Troglodytes or Pithecus, than these apes are from the Lemur, and still more from the Galeopithecus or the Cheiromys, the other queries will need no separate solution. ”

“ The most certain propositions entertained by the human physiologist, those upon which the scientific practice of the healing art depends, are largely, or wholly, based on the results of experiments on animals. The poison which hurts them does not leave us unscathed ”

“ They are capable of shame and of sorrow; and though they may have no logic nor conscious ratiocination, no one who has watched their ways can doubt that they possess that power of rational cerebration which evolves reasonable acts from the premises furnished by the senses—a process, be it observed, which takes fully as large a share as conscious reason in human activity. ”

“ Linnæus was content to rank man and the apes in the same order, Primates, ranging in terms of zoological equality, the genera, Homo, Sima, Lemur, and Vespertilio. Among more modern zoologists of eminence, Schreber, Goldfuss, Gray, and Blyth, have followed Linnæus, in being unable to see the necessity of distinguishing man ordinally from the apes. ”

“ It is generally admitted that no very strict line of demarcation is traceable between the middle and posterior lobes; anatomists being content to accept Cuvier's curt definition:—
"La partie du cerveau située au-dessus du cervelet est ce qu'on nomme le lobe postérieur du cerveau." ”

“ For whether, as some think, man is, by his origin, distinct from all other living beings, or whether, on the other hand, as others suppose, he is the result of the modification of some other mammal, his duties and his aspirations must, I apprehend, remain the same. ”

“ Owen, that the determination of the difference between Homo and Pithecus is the 'anatomist's difficulty.' ↑ Professor Owen on the Characters, &c, of the Class Mammalia, l. c., p. 33. ↑ L'homme ne forme ni une espèce ni une genre comparable aux Primates. L'homme à lui seul constitue un regne à part—le Regne humain."—Resumé des Leçons sur l'Embryologie Anthropologique, Comptes Rendus, 1851. ”

“ Without doubt such characters are to be found; and in all probability, as in the case of any other two distinct genera, the more carefully and minutely our inquiries are carried out, the greater will be the number of these differentiæ. ”