198 LECTURE VII. 



open basilar suture, as well as the traces (in Owen's skull) of 

 the intermaxillary suture, all these strike us at the first glance 

 as animal characters. 



Fig. 72. Chimpanzee skull, side view. 



We need only place the skulls of the Negro, chimpanzee 

 and idiot side by side, to show that the idiot holds in every 

 respect an intermediate place between them. The only human 

 characters which the idiot shows in his skull are the gapless 

 serried teeth, and the somewhat projecting chin. The closure 

 of the sutures must by no means be considered as the cause of 

 the arrested cerebral development. In most old idiots the 

 sutures of the upper surface are still movable, those on the 

 sides are frequently closed, whilst at the base they are open as 

 in the ape. The occiput is sometimes square, at times round, 

 but very large compared to the forehead ; the internal pro- 

 cesses of the skull bear so far an infantile character, from their 

 being rounded, never sharply angular. 



We may, therefore, summarise the idiotic forms by stating, 

 that in their brains and skulls the resemblance to the human 

 standard has been diminished by the arrested development of 

 the anterior cerebral lobes, and that only the secondary human 

 character, the serried set of teeth and the projecting chin, have 

 been preserved. If a fossil microcephalic skull were found, 

 without a lower jaw and an upper row of teeth, every naturalist^ 



* Query. — Editok. 



