But it is interesting to note that no one ape most closely approaches man in all anatomical respects.  Thus among the anthropoids the orang is perhaps most similar to man in cerebral structure, the chimpanzee in form of skull, the gorilla in feet and hands.  No evolutionist would claim that any existing ape represents the ancestor of man.  The anthropoids represent very probably the culmination of at least three distinct lines of development.  But we must remember that in early tertiary times apes occurred all over Europe, and probably Asia, many degrees farther north than now.  In those days, as later, the fauna and flora of northern climates were superior in vigor and height of development to that of Africa or Australia.  It is thus, to say the least, not at all improbable that there existed in those times apes considerably, if not far, superior to any surviving forms.  Whether the palaeontologist will find for us remains of such anthropoids is still to be seen.

But you will naturally ask, “Is there not, after all, a vast difference between the brain of man and that of the ape?” Let us examine this question as fully as our very brief time will allow.  Considerable emphasis used to be laid on the facial angle between a line drawn parallel to the base of the skull and one obliquely vertical touching the teeth and most prominent portion of the forehead.  Now this angle is in man very large—­from seventy-five to eighty-five degrees, or even more, and rarely falling below sixty-five degrees.  But this angle depends largely on the protrusion of the jaws, and varies greatly in species of animals showing much the same grade of intelligence.  In some not especially intelligent South American monkeys the facial angle amounts to about sixty-five degrees.  In this respect the skull of a chimpanzee reminds us of a human skull of small cranial capacity and large jaws, in which the cranium has been pressed back and the jaws crowded forward and slightly upward.

The weight of the brain in proportion to that of the body has been considered as of great importance, and within certain limits this is undoubtedly correct.  Thus, according to Leuret, the weight of the brain is to that of the whole body:  In fish, 1:5,668; in reptiles, 1:1,320; in birds, 1:212; in mammals, 1:186.  These figures give the averages of large numbers of observations and have a certain amount of value.  But within the same class the ratio varies extraordinarily.  Thus the weight of the brain is to that of the whole body:  In the elephant, 1:500; in the largest dogs, 1:305; in the cat, 1:156; in the rat, 1:76; in the chimpanzee, 1:50; in man, 1:36; in the field-mouse, 1:31; in the goldfinch, 1:24.