700 NERVOUS SYSTEM. 



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. 



It is a fact now generally admitted in pathology, that loss of cerebral substance from 

 repeated hemorrhage is sooner or later followed by impairment of the intellectual facul- 

 ties. 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 

 connection of ideas, abnormal irritability of temper with a childish susceptibility to petty 

 or imaginary annoyances, easily- excited emotional manifestations, and a variety of phe- 

 nomena denoting abnormally feeble intellectual power, following any considerable disor- 

 ganization of cerebral substance. In short, pathological conditions of the brain all go to 

 show that the intellectual faculties are connected with 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. There are on record 

 numerous 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 19|, 

 25f, and 22 ounces, in three idiots, whose ages were, respectively, sixteen, forty, and 

 fifty years. A case has been reported by Mr. Gore, of an idiotic woman, forty-two years 

 of age, whose brain weighed ten ounces and five grains ; and one by Mr. Marshall, of an 

 idiotic boy, twelve years old, whose brain weighed but 8^ ounces. Mr. Bradley, in a late 

 number of the Journal of Anatomy and Physiology, gives an elaborate description of the 

 brain of an idiot, thirty-five years of age, extremely emaciated at the time of his death, 

 when he weighed but sixty pounds. The encephalon, including the cerebrum, cerebellum, 

 and pons, weighed twenty-eight ounces, and the proportion of the cerebellum to the 

 cerebrum was as 1 to 5*5. In the healthy adult male of ordinary weight, the encephalon 

 weighs fifty ounces, and the proportion of the cerebellum to the cerebrum is as 1 to 8^. 

 Mr. Bradley calls attention to the proportion of the cerebellum to the cerebrum in this 

 case, stating that this is common in the encephalon of idiots. In idiots, the weight of the 

 body is generally much below the normal standard ; and, in the case reported by Bradley, 

 the proportionate weight of the encephalon to that of the entire body is even greater than 

 in the healthy adult. This point, however, cannot be admitted as an argument against 

 the fact that congenital idiocy is usually attended with an abnormally small development 

 of the hemispheres. Most idiots take little or no exercise; they are under-sized, and 

 have but little muscular vigor ; and it is probable that the imperfect development of the 

 body is more or less a consequence of the abnormal cerebral condition. We might com- 

 pare the weight of the body in Mr. Bradley's case with that of a child from seven to 

 fourteen years of age ; and, at this period of life, according to the tables compiled by 

 Quain, the average weight of the encephalon is 45'96 ounces, for the male, and 40*78 

 ounces, for the female. 



The statements just made with regard to the brains of idiots refer to cases charac- 

 terized by complete absence of intelligence, and farthermore, probably, by very small 

 development of the body. On the other hand, there are instances of idiocy, the body 

 being of ordinary size, in which the weight of the encephalon is little if any below the 

 average. Le'lut reports several cases of this kind. In one of these, a deaf-mute idiot, 

 forty-three years of age, a little above the ordinary stature, presenting " idiocy of the 

 lowest degree; almost no sign of intelligence; no care of cleanliness," the encephalon 

 weighed 48-32 oz. Other cases of idiots of medium stature are given, in which the brain 

 weighed but little less than the normal average. In the West Riding Lunatic Asylum 

 Reports, London, 1876, p. 19, is a report of the case of a congenital imbecile, aged thirty 

 years, height five feet and eight inches, died of phthisis, whose brain weighed 70 oz. 

 These facts illustrate the difficulty of subordinating individual observations to any general 

 rule, and this is particularly marked with regard to the brain, the structure of which is 

 so complex and difficult of investigation. 



