Twenty-fourth annual meeting. 



ous, progressive change, according to certain laws and by means of resident forces. 

 . . . Commencing with the lowest, unicelled, microscopic organism, and passing 

 np the animal scale as it now exists, we find a series of forms similar to, though not 

 identical with, the embryonic series. Here we again find cell added to cell, tissue to 

 tissue, organ to organ, and function to function, the animal body becoming more 

 and more complex in structure, in the mutual action of its correlated parts and the 

 mutual action with the environments," until we reach the highest complexity of 

 structure and of internal and external relations only in the highest animals.'" 



Of the Origin of Man. It is not yet possible to trace the descent of man back to 

 the primeval protozoan, which was the origin of all life. His genealogy can only 

 be approximated, and must forever remain a mystery. The process of the evolu- 

 tion of animal life does not form a continuous ladder from the lowest to the highest, 

 for there are many breaks and missing links. The protozoan is the lowest sub- 

 kingdom, the vertebrate is the highest, but the line of ascent from the one to the 

 other is not homogeneous, nor continuous, nor symmetrical. 



Man is a vertebrate animal, but the course of his descent, even after the differ 

 entiation of the mammalia from the vertebrate series, is very uncertain. He retains 

 morphological affinities with so many and sometimes widely separate branches, that 

 he is not related so very closely to any of them. He most resembles the anthropoid 

 apes, of course, but it is only by parallel — not direct — descent that he is related to 

 them. He is not descended from them, but from a common ancestral form with 

 them, which, in its turn, was descended from a common progenitor of other verte- 

 brates. When the genealogy of man shall have been worked out as completely as 

 that of the horse, for instance, we shall have a wonderful biological history, but for 

 the present that history is incomplete. Darwin says ("Descent of Man"): "The 

 most ancient progenitors in the kingdom of the vertebrata probably consisted of a 

 group of marine animals resembling the larva? of existing ascidians. These animals 

 probably gave rise to a group of fishes as lowly organized as the lancelet, and from 

 these the ganoids and others, like the lepidosiren, must have been developed. From 

 such a fish would arise the amphibians — the fish-like reptiles — and from these the 

 true reptiles and birds. These are closely connected with the monotremata, which 

 connect mammals and reptiles in a degree; but the line of descent of the higher ver- 

 tebrate classes — mammals, birds, reptiles — from the lower classes — amphibians, 

 fishes, etc. — is obscure. But from the monotremata arose the marsupials, which 

 were the early progenitors of the placental mammals. We may thence ascend to the 

 lemuridse, and thence the interval is not very wide to the simiadte. The simiadse 

 then branched into two great stems — the new-world and the old-world monkeys — 

 and from the latter, at a remote period, man proceeded." Not from the forms that 

 now exist, however, but from a common progenitor with them. Our study of the 

 face will, therefore, need to be comparative, perhaps, more than genealogical, except 

 in the few instances in which there is evident descent. There are gradation stages 

 plainly evident, as the facial parts arose from the lower, headless forms of animals, 

 which, possessed neither face nor separate sense organs. 



Of the Special-Sense Organs and the Origin of the Face from Them. The mere 

 structures of the face arose from its parts having been evolved and erected for ths 

 accommodation of some of the special-sense organs. In fact, we must place its 

 origin at the time of the differentiation of the special senses, when special structures 

 were demanded for their supjjort and protection. We follow backward along the 

 path of the evolution of the face, and find its origin in the differentiation of the four 

 facial senses. But, previous to this differentiation of sensation into the various 

 special senses, we observe that unspecialized nervous organization preceded func- 

 tion, unless, indeed, sensation exists without and preceded nervous organization. 



