STRUCTURE OF THE BRAIN 



other respects; viz., the lower members of the Platyrhine 

 group." 



So far as the structure of the adult brain is concerned, 

 then, the very considerable additions to our knowledge, 

 which have been made by the researches of so many investi- 

 gators, during the past ten years, fully justify the statement 

 which I made in 186S. But it has been said that, admitting 

 the similarity between the ad alt brains of man and apes, 

 they are nevertheless, in reality, widely different, because 

 they exhibit fundamental differences in the mode of their 

 development. No one would be more ready than I to admit 

 the force of this argument, if such fundamental differences 

 of development really exist. But I deny that they do exist. 

 On the contrary, there is a fundamental agreement in the 

 development of the brain in men and apes. 



Gratiolet originated the statement that there is a funda- 

 mental difference in the development of the brains of apes 

 and that of man — consisting in this; that, in the apes, the 

 eulci which first make their appearance are situated on 

 the posterior region of the cerebral hemispheres, while, 

 in the human foetus, the eulci first become visible on the 

 frontal lobes." 



This general statement is based upon two observations, 

 the one of a Gibbon almost ready to be born, in which the 



{)osterior gyri were "well developed," while those of the 

 rontal lob^ were "hardly indicated"" (1. c, p. 39), and 



1* "Chez tons les singes, les plis post^rieura se d^veloppent lea premiers; 

 lea plis snt^rieurs se d^veloppent plua tard, auaai la vertbbre occipitale et la 

 pari^tale sont-elles relativement tres-grandea chez le foetus. L'Homme pr^ 

 seute une exception remarquable quant & I'^poque de I'apparition des plis 

 frontauz, qui sont les premiers indiqu^s ; mais le diveloppement g^n^ral du lobe 

 frontal, envisage senlement par rapport 4 son volume, suit les mSmes lois que 

 dans les singes." Oratiolet, "M^oire sur les plis c^r^raux de I'Homme 

 et dea Primates," p. 39, tab. iv. fig. 3. 



'" Gratiolct's words are (Ji. c, p. 39): "Dans le foetus dont il s'agit lea plis 

 c^r^braux post^rieurs sent bien developp^, tandis que les plis du lobe frontal 

 sont 4 peine indiqnfe." The figure, however (PI. iv. fig. 3), shows the flaaure 

 of Rolando, and one of the frontal sulci, plainly enough. Nevertheless, 

 M. Alix, in his "Notice sur les ttavaux anthropologiques de Gratiolet" 

 ("M^m. de la Soci^ d'Anthropologie de Paris," 1868, p. 32), writes thus: 

 Gratiolet a eu entre les mains le cerveau d'un foetus de Gibbon, singe Eminem- 

 ment sup^rieur, et tellement rapproch^ de I'orang, que des natnralistes trds 

 Comp4tent8 I'ont rang^ parmi Im snthropoides. H. Huxley, par exemple^ 

 n'hesite pas sur oe point. Eh bien, c'est sur le cerveau d'un foetns de Gibbon 

 que Gratiolet a vn fes ctrconm^utitms du lobe temporo-^h^noidal d^d divelopp4«$ 

 itrs-qu'tt H'esdste pas encore de pHa mr le foSe /rontal. H ^tait done bieo 

 sntoris^ A dite qne, chez I'homme les circonvolutioDS apparaisaent d'a en •, 

 tandis que chez les singes eltes se ddveloppent d'- en a." 



