Without further preface, I shall proceed to consider as briefly as possible the main arguments adduced by Mr. Darwin in support of this conclusion.[364] Those which are derived from the consideration of physical data appear to me to be of comparatively small importance, since they may be admitted without seriously affecting the question at issue. They are almost all connected with the fact that man is “constructed on the same general type or model with other mammals.” Thus it is with the brain, every chief fissure and fold of which is declared to be developed in the brain of the orang equally with that of man. Their constitutional habit, however, appears also to be the same. Thus man and monkeys are liable to many of the same non-contagious diseases; medicines produce the same effect on both, and most mammals exhibit the mysterious law of periodicity in various diseases. These are interesting facts, but the most important for the argument of the ape-descent of man are those which show the existence in the human body of certain rudimentary organs and structures which are fully developed with some of the lower animals. It is possible, however, to explain this phenomenon without having recourse to the hypothesis of a simple ape-descent; even if it be admitted with M. Broca, that in the parallel between man and the anthropoids, the comparison of organs shows only some slight differences.[365] This may be granted even as to the brain, and that “the immense superiority of man’s intelligence depends, not on the anatomical structure of his brain, but on its volume and power.”[366] But then, if such is the case, it is all the more difficult to account for the vast difference which, says Broca, a comparison of function reveals, and which led M. Gratiolet to exclaim that, although man is indeed by his structure a monkey, yet by his intelligence he is a God.[367]