GENERAL USES OF THE CEREBRUM 589 



This will perhaps explain some of the exceptions above indicated ; but 

 an additional explanation may be found in differences in the quality of 

 brain-substance in different individuals, irrespective of the size of the 

 cerebral hemispheres. One evidence that these differences in the 

 quality of intellectual working matter exist is that some small brains 

 actually accomplish more and better work than some large brains. 

 This may be due to differences in training, to the extraordinary develop- 

 ment, in some individuals, of certain qualities, to intensity and pertinacity 

 of purpose, capacity for persistent labor in certain directions, a fortu- 

 nate direction of the mental efforts, opportunity and circumstances, etc. ; 

 but aside from these considerations, it is probable that there are 

 important individual differences in the quality of nervous matter. 



Facial Angle. It is not necessary to enter into an extended discus- 

 sion of the relations of the facial angle to intelligence. It was proposed 

 by Camper to take the angle made at the junction of two lines, one 

 drawn from the most projecting part of the forehead to the alveolae of 

 the teeth of the upper jaw, and another passing horizontally backward 

 from the lower extremity of the first line, as the facial angle. This 

 angle is to a certain extent a measure of the projection of the anterior 

 lobes of the brain. A number of observations on the facial angle in 

 different races has been made by Camper and by other physiologists 

 and ethnologists. These show, in general terms, that the angle is 

 larger in man than in any of the inferior animals and is largest in those 

 races that possess the greatest intellectual development. 



Pathological Observations. 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 faculties. 

 This point frequently is difficult to determine in an individual 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 childish susceptibility to petty or imaginary annoyances, 

 easily-excited emotional manifestations and a variety of phenomena de- 

 noting abnormally feeble intellectual power following any considerable 

 disorganization of cerebral substance. In short, pathological conditions 

 of the brain all go to show that the intellectual faculties are directly 

 connected with the cerebral hemispheres. 



In idiots the brain usually is of small size, although there are excep- 

 tions to this rule. In two cases of adult idiots, reported by Tiedemann, 

 the brain was about one-half of the normal weight. The brain of an 

 idiotic woman, forty-two years of age, reported by Gore, weighed ten 

 ounces and five grains (about 284 grams). It has been observed, also, 

 that the cerebellum is not proportionally diminished in size in idiots 



