712 [June 18, 



examination shows that the malformation is not due to a simple 

 arrest occurring so late in foetal life, but commences much earlier in 

 the parts at the base of the cerebrum, and then influences the evolu- 

 tion of the superficial parts of the hemispheres. The corpora striata 

 appear to be specially affected, and through these the whole hemi- 

 spheres, but the frontal lobe especially. The interest of this obser- 

 vation in a general physiological view, and especially in regard to the 

 mental condition of idiots, is pointed out. 



7. It is not certain whether the idiots' brains had undergone any 

 local evolutional change as the result of education or training. 



8. It is certain that they had increased somewhat in size after the 

 general cessation of evolutional changes in their form. 



9. The idiots' brains differ the woman's being more developed 

 on the whole, especially in the temporal regions. Her mental powers 

 were also greater. 



10. These idiot brains are somewhat less developed than the two 

 microcephalic cerebra figured by Leuret and Gratiolet. 



1 1 . The convolutions in the idiots' brains are more simple than 

 those of the higher Apes, and approach, in this respect, those of 

 still lower Quadrumana. But the points of difference between the 

 idiots' brains and those of the Quadrumana are very decided. They 

 are human cerebra, although so imperfectly developed. They show 

 a general conformity to the cerebral plan of the Primates generally ; 

 but already they manifest special human characters. 



In regard to the internal structure of the cerebrum and cere- 

 bellum, many facts are noticed. The commissural fibres of the 

 corpus callosum are very imperfectly developed. The lateral ven- 

 tricles and their contents generally are fairly developed; but the 

 corpora striata are very small. The cerebellum is well developed in 

 all its parts in both idiots, but is not perfectly so in either. It is 

 larger in the idiot boy ; but the transverse commissural fibres are 

 much less developed in him than in the woman. In accordance 

 with Malacarne's statements, the laminse are fewer in number in 

 both idiots' brains than in the perfect brain. The cerebellum is not 

 merely larger, but much more developed in its form than the cere- 

 brum, and it certainly continued to be developed to a much later 

 period. 



In a postscript-note, dated August 6th, 1863, the author gives an 



