THE RACES OF MAN. 233 



have to be grouped among fishes. But it is equally true that a tad- 

 pole is very different from any known fish. 



In like manner, the brain of a human fcetus, at the fifth month, 

 may correctly be said to be, not only the brain of an ape, but that of 

 an Arctopithecine or marmoset-like ape; for its hemispheres, with 

 their great posterior lobster, and with no sulci but the sylvian and 

 the calcarine, present the characteristics found only in the group of 

 the Arctopithecine Pnmates But it is equally true, as Gratiolet 

 remarks, that in its widely open sylvian fissure it differs from the 

 brain of any actual marmoset. No doubt it would be much more 

 similar to the brain of an advanced foetus of a marmoset. But we 

 know nothing whatever of the development of the brain in the mar- 

 mosets. In the Platyrrhini proper, the only observation with which 

 I am acquainted is due to Pansch, who found in the brain of a fcetal 

 Cebtis Apella, in addition to the sylvian fissure and the deep calcarine 

 fissure, only a very shallow antero-temporal fissure {scissure parallele 

 of Gratiolet). 



Now this fact, taken together with the circumstance that the 

 antero-temporal sulcus is present in such Platyrrhini as the Saimiri, 

 which present mere traces of sulci on the anterior half of the exterior 

 of the cerebral hemispheres, or none at all, undoubtedly, so far as it 

 goes, affords fair evidence in favor of Gratiolet's hypothesis, that the 

 posterior sulci appear before the anterior, in the brains of the 

 Platyrrhini. But it by no means follows that the rule which may 

 hold good for the Platyrrhini extends to the Catarrhini. We have 

 no information whatever respecting the development of the brain in 

 the Cynomorpha; and as regards the Anthroporaarpha, nothing but 

 the account of the brain of the Gibbon, near birth, already referred 

 to. At the present moment there is not a shadow of evidence to show 

 that the sulci of a chimpanzee's or orang's brain do not appear in the 

 same order as a man's. 



Gratiolet opens his preface with the aphorism : "II est dangereux 

 dans les sciences de conclure trop vite." I fear he must have for- 

 gotten this sound maxim by the time he had reached the discussion 

 of the differences between men and apes in the body of his work. No 

 doubt the excellent author of one of the most remarkable contribu- 

 tions to the just understanding of the mammalian brain which has 

 ever been made, would have been the first to admit the insufficiency 

 of his data had he lived to profit by the advance of inquiry. The 

 misfortune is that his conclusions have been employed by persons 

 incompetent to appreciate their foundation as arguments in favor of 

 obscurantism.* 



But it is important to remark that, whether Gratiolet was right or 

 wrong in his hypothesis respecting the relative order of api>earance 

 of the temporal and frontal sulci, the fact remains, that before either 

 temporal or frontal sulci appear, the foetal brain of man presents 

 characters which are found only in the lowest group of the PHmates 

 (leaving out the Lemurs); and that this is exactly what we should 

 expect to be the ca.se if man ha.s resulted from the gradual modifica- 

 tion of the same form as that from which the other Primates have 

 sprung. 



* For example, M. I'Abbe Lecomte in his terrible pamphlet, " Le Darwin- 

 ismo et I'origine de rHomme," 1873. 



