GENERAL USES OF THE CEREBRUM. 619 



Development of the Cerebrum in Different Races of Men and in Different 

 Individuals. It may be stated as a general proposition, that in the different 

 races of men, the cerebrum is developed in proportion to their intellectual 

 power; and in different individuals of the same race, the same general rule 

 obtains. Still, this law presents marked exceptions. Certain brains in an 

 inferior race may be larger than the average in the superior race ; and it is 

 frequently observed that unusual intellectual vigor is co-existent with a small 

 brain, and the reverse. These exceptions, however, do not take away from 

 the force of the original proposition. As regards races, the rule is found to 

 be invariable, when a sufficient number of observations are analyzed, and the 

 same holds true in comparing a large number of individuals of the same race. 

 Average men have an advantage over average women of about six ounces 

 (170 grammes) of cerebral substance ; and while many women are far superior 

 in intellect to many men, such instances are not sufficiently frequent to 

 invalidate the general law, that the greatest intellectual capacity and mental 

 vigor is coincident with the greatest quantity of cerebral substance. If the 

 view, which is in every way reasonable, be accepted, that the gray substance 

 alone of the cerebral hemispheres is directly connected with the mind, it 

 would be necessary, in comparing different individuals with the view of 

 establishing a definite relation between brain-substance and intelligence, to 

 estimate the quantity of gray matter ; but it is not easy to see how this can 

 be done with any degree of accuracy. 



It is undoubtedly true that proper training and exercise develop and 

 increase the vigor of the intellectual faculties, and that thereby the brain is 

 increased in power, as are the muscles under analogous conditions. 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 fact may be due to differences in train- 

 ing, to the extraordinary development, in some individuals, of certain quali- 

 ties, to intensity and pertinacity of purpose, capacity for persistent labor in 

 certain directions, a fortunate direction of the mental efforts, opportunity and 

 circumstances, etc. ; but aside from these considerations, it is exceedingly 

 probable that there are important individual differences in the quality of 

 nervous matter. 



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

 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 ex- 

 tremity 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 upon the facial angle in different races has been made by Camper 

 and by other physiologists and ethnologists. These show, in general terms, 



