LECTURE VI. 167 



nearly smootli hemisplieres in the fiftli montli of tlie human 

 fcetus and the uncouvoluted brains of the small clawed mon- 

 keys. There is also a decided resemblance in the greater sym- 

 metry and scantiness of the convolutions of both hemispheres, 

 the poor, compact, less furrowed and undivided frontal convo- 

 lutions in the human foetus in the sixth and seventh month on 

 the one side, and a number of superior apes up to the anthro- 

 poid apes on the other." 



I would finally ask whether this development law has been 

 traced in all races ? As far as I am aware, no anatomist has 

 examined Negro and Hottentot embryos of the fifth and 

 seventh month. But we also know that skull and brain are 

 so intimately connected, that they condition each other ; we 

 know, and Gratiolet has pointed it out, that the Negro skull 

 follows, as regards the closing of the sutures, a different law 

 from the skull of the white man ; that the frontal and coronal 

 sutures, as in the ape, close earlier than the posterior suture, 

 whilst the reverse is the case in the white man. Would it 

 then be so very hazardous to assume that this same simian 

 development of the skull in the Negro extends also to the 

 brain ? 



The second point refers to the microcephali. These unfor- 

 tunate creatures who, according to Bischofi", are not men, will 

 just prove to us that the human brain preserves its type under 

 all circumstances. 



The cerebral form of the microcephaK consists essentially in 

 an arrest of development, which, however, does not equally 

 affect the whole brain, but chiefly the frontal lobes. The 

 brain of all microcephah hitherto examined has in the anterior 

 parts the same type as that of the anthropoid apes, being 

 arrested in that stage " in which the embryonal human brain 

 exhibits less developed convolutions and sulci, as is always 

 observed in simian brains." In the posterior part the micro- 

 cephalous brain is even behind the simian type. The cere- 

 bellum is not perfectly covered by the posterior lobe, whilst 

 in all apes it is covered. This condition reminds us of the 

 brain of the carnivora, and the form of the foetus between the 

 third and fourth month. 



