2<;8 THE POPULAR SCIENCE MONTHLY. 



bral mass and structure. It will also include inquiries concerning the 

 time taken in completing mental evolution, and the time during which 

 adult mental power lasts ; as well as certain most general traits of 

 mental action, such as the greater or less pei'sistence of emotions and 

 of intellectual processes. The connection between the general mental 

 type and the general social type should also be here dealt with. 



In the second division may be conveniently placed apart, inquiries 

 concerning the relative mental natures of the sexes in each race. 

 Under it Avill come such questions as these : What differences of 

 mental mass and mental complexity, if any, existing between males 

 and females, are common to all races ? Do such differences vary in 

 degree, or in kind, or in both? Are there reasons for thinking that 

 they are liable to change by increase or decrease ? What relations 

 do they bear in each case to the habits of life, the domestic arrange- 

 ments, and the social arrangements ? This division should also in- 

 clude in its scope the sentiments of the sexes toward one another, 

 considered as varying quantitatively and qualitatively ; as well as 

 their respective sentiments toward offspring, similarly varying. 



For the third division of inquiries may be reserved the more spe- 

 cial mental traits distinguishing different types of men. One class of 

 such specialties results from differences of proportion among faculties 

 possessed in common ; and another class results from the presence in 

 some races of faculties that are almost or quite absent from others. 

 Each difference in each of these groups, when established by compari- 

 son, has to be studied in connection with the stage of mental evolu- 

 tion reached, and has to be studied in connection with the habits of 

 life and the social development, regarding it as related to these both 

 as cause and consequence. 



Such being the outlines of these several divisions, let us now con- 

 sider in detail the subdivisions contained within each. 



I. Under the head of genei'al mental evolution we may begin 

 with the trait of 



1. Mental Mass. Daily experiences show us that human beings 

 differ in volume of mental manifestation. Some there are whose in- 

 telligence, high though it may be, produces little impression on those 

 around ; while there are some who, when uttering even commonplaces, 

 do it so as to affect listeners in a disproportionate degree. Comj^ari- 

 son of two such makes it manifest that, generally, the difference is 

 due to the natural language of the emotions. Behind the intellectual 

 quickness of the one there is not felt any power of character; while 

 the other betrays a momentum capable of bearing down opposition 

 a potentiality of emotion that has something formidable about it. 

 Obviously the varieties of mankind differ much in respect of this trait. 

 Apart from kind of feeling, they are unlike in amount of feeling. The 

 dominant races overrun the inferior races mainly in virtue of the 



