BRUTE-MAN'S HELPLESSNESS 17 



tion from the hereditary type. This is variation in 

 forms of life lower than sexual, the result of reac- 

 tions arising in the environment. 



This kind of variation obviously is the cause of 

 the origin of somatic cells, — cells which have so 

 varied from their ancestral type that they have lost 

 the power of reproducing the organism of the kind 

 from which they have sprung, but which can repro- 

 duce their own type of cells, out of which the special 

 organs of specialized individuals are formed. As 

 these special organs are of survival value only when 

 with otherwise specialized organs, each operating 

 in its special line, they co-operate so as to ward off 

 the dangers of external interference with internal 

 conditions, and establish that harmony of function 

 on which the life and welfare of all highly specialized 

 individuals depend; it follows that this kind of 

 variative influences can have but a slight effect, if 

 any, on highly specialized forms of life. See Appen- 

 dix, Note IV. 



Limiting consideration in this place to the more 

 important among his external physical traits, man 

 is distinguished from the quadrumana mainly by: 



1. Arms proportionally shorter. 



2. Finger tips, fingers, and thumbs in the upper 

 extremities, mainly specialized to sensations of 

 touch, as distinguished from the corresponding 

 organs of the quadrumana, which are almost exclu- 

 sively adapted to prehension and locomotion. 



3. Feet at the lower extremities, distinguished 



