338 PHYSIOLOGY CHAP. 



intents and purposes agree with those he : had already reached. 

 He found that the upper frontal sulcus is more frequently divided 

 in Hereros than in Indians and Japanese, whereas this division is 

 less frequent in the median frontal sulcus; also that the single 

 precentral sulcus occurs more frequently in Hereros and Japanese 

 than in Indians, and that it is very seldom found in Esthonians, 

 Lithuanians, and Poles; that the upper frontal sulcus is never 

 entirely separated from the precentral sulcus in Indians, whereas 

 this separation occurs most frequently in the inhabitants of Java 

 and is rather rarer in Hereros and Japanese ; that the lower 

 precentral sulcus usually joins the lower frontal sulcus in the 

 Dutch and Swedes, frequently does so in Japanese and still more 

 often in Poles, Esthonians, Lithuanians, but is never so joined in 

 the brains of Japanese ; it is least often seen in Hereros, in whose 

 brains separation with a superficial bridge predominates,, whereas 

 in Indians separation with a deep bridge is commoner ; that a 

 larger number of paramesial frontal sulci is found in Japanese 

 brains ; that the lower frontal sulcus is more frequently divided 

 in Indians and Japanese than in Hereros and Swedes ; that the 

 frontal marginal sulci are more divided in Indians and Japanese, 

 less in Hereros, and still less in Europeans. There are also 

 variations in the fissure of Rolando, which have apparently a 

 relation to sex. 



Another fact to which Sergi (1910) attaches great importance 

 is the development of the frontal lobe. This development varies 

 considerably, but does not correspond to the degree of intellectual 

 and social development reached by the different races. Great 

 development of the frontal lobe as compared with that of the 

 parietal and occipital lobe does not, therefore, as is thought by 

 many, distinguish the brain of the higher races from that of the 

 lower ones. This suggests that the frontal lobe is not the 

 anatomical seat of the highest psychical functions a statement 

 in agreement with the conclusions arrived at in the last chapter 

 of Vol. III., in which we proved these functions to be localised in 

 the central and posterior regions of the cerebral cortex. 



Kohlbrugge (1911) considers that the results hitherto obtained 

 do not justify the conclusion that the weight of the brain, the 

 complexity of its convolutions, and the size of the frontal lobe 

 invariably increase in proportion to the degree of civilisation or 

 intelligence reached by either individuals or races. 



A question of the highest importance which is very frequently 

 discussed is the permanence of different morphological racial 

 characteristics. That there is no such thing as absolute unchange- 

 ability is clearly proved by the possibility of crossing different 

 races, the results of which are the well-known half-breeds or 

 mulattos, whose characteristics are a mixture of those of both 

 parents. It is, however, open to question whether these half- 



