But there is another characteristic of the brain which seems to bear a close relation to the degree of intelligence.  The surface of the human brain is not smooth but covered with convolutions, with alternating grooves or sulci, which vastly increase its surface and thus make room for more gray matter.  Says Gratiolett:  “On comparing a series of human and simian brains we are immediately struck with the analogy exhibited in the cerebral forms in all these creatures.  There is a cerebral form peculiar to man and the apes; and so in the cerebral convolutions, wherever they appear, there is a general unity of arrangement, a plan, the type of which is common to all these creatures.”  Professor Huxley says:  “It is most remarkable that, as soon as all the principal sulci appear, the pattern according to which they are arranged is identical with the corresponding sulci in man.  The surface of the brain of the monkey exhibits a sort of skeleton map of man’s, and in the man-like apes the details become more and more filled in, until it is only in minor characters that the chimpanzee’s or orang’s brain can be structurally distinguished from man’s.”

The facts of anatomy, at least, are all against us.  Struggle as we may, be as snobbish as we will, we cannot shake off these poor relations of ours.  Our adult anatomy at once betrays our ancestry, if we attempt to deny it.  Read the first chapter of that remarkable book by Professor Drummond on the “Ascent of Man,” the chapter on the ascent of the body, and the second chapter on the scaffolding left in the body.  The tips of our ears and our rudimentary ear muscles, the hair on hand and arm, and the little plica semilunaris, or rudimentary third eyelid in the inner angle of our eyes, the vermiform appendage of the intestine, the coracoid process on our shoulder-blades, the atlas vertebra of our necks—­to say nothing of the coccyx at the other end of the backbone—­many malformations, and a host of minor characteristics all refute our denial.

If we appeal from adult anatomy to embryology the case becomes all the worse for us.  Our ear is lodged in the gill-slit of a fish, our jaws are branchial arches, our hyoid bone the rudiment of this system of bones supporting the gills.  Our circulation begins as a veritable fish circulation; our earliest skeleton is a notochord; Meckel’s cartilage, from which our lower jaw and the bones of our middle ear develop, is a whole genealogical tree of disagreeable ancestors.  Our glandula thyreoidea has, according to good authorities, an origin so slimy that it should never be mentioned in polite society.  The origin of our kidneys appears decidedly vermian.  Time fails me to read merely the name of the witnesses which could be summoned from our own bodies to witness against us.

Even if the testimony of some of these witnesses is not as strong as many think, and we have misunderstood several of them, they are too numerous and their stories hang too well together not to impress an intelligent and impartial jury.  But what if it is all true?  What if, as some think, our millionth cousin, the tiger or cat, is anatomically a better mammal than I?  His teeth and claws and magnificent muscles are of small value compared with man’s mental power.