338 NEKVOUS SYSTEM. 



confirmed the conclusions to be drawn from these pathologi- 

 cal facts. In frogs, fishes, and birds, when one hemisphere 

 has been removed, the evidences of feebleness of the muscles 

 of the opposite side are not very marked ; but they are quite 

 distinct in the adult mammalia. Yulpian noted, in experi- 

 ments upon dogs, that the destruction of a portion of one 

 cerebral hemisphere produced feebleness, but a very incom- 

 plete paralysis of motion upon the opposite side. 1 



It is a fact now generally admitted in pathology, that loss 

 of cerebral substance from repeated haemorrhage is sooner 

 or later followed by impairment of the intellectual faculties. 

 This point it is frequently difficult to determine in a single 

 instance, but an analysis of a sufficient number of cases 

 shows impaired memory, tardy, inaccurate, and feeble con- 

 nection of ideas, abnormal irritability of temper, with a child- 

 ish susceptibility to petty or imaginary annoyances, easily- 

 excited emotional manifestations, and a variety of phenom- 

 ena denoting abnormally feeble intellectual power, following 

 any considerable loss of cerebral substance. In short, patho- 

 logical conditions of the brain all go to show that the intel- 

 lectual faculties reside in the cerebral hemispheres. 



As a final argument drawn from pathology, in favor of 

 the view just stated, we have only to allude to the size of 

 the brain in certain cases of idiocy. Prof. Hammond, in his 

 admirable work on " Diseases of the Nervous System," has 

 cited several examinations of the brain in idiots, in which 

 this organ has been found to be less than one-half of the 

 ordinary weight ; as the cases reported by Tiedemann, of 

 19f, 25f , and 22^- ounces, in three idiots, whose ages were, 

 respectively, sixteen, forty, and fifty years. 2 A case was 

 reported by Mr. Gore, of an idiotic woman, forty-two years 

 of age, whose brain weighed ten ounces and five grains ; 3 



1 VULPIAN, Systcme nerveux, Paris, 1866, p. 677. 



2 HAMMOND, Diseases of the Nervous System, New York, 1871, p. 326. 



3 GORE, Notice of a case of Micro-ccphaly. Anthropological Review, London, 

 1863, No. i., p. 170. 



