PRIMITIVE MAN. 331 



fche strong points often dwelt on by Spencer in his 

 "Biology."* 



" But the experiences which most clearly illustrate 

 to us the process of general evolution are our ex- 

 periences of special evolution, repeated in every plant 

 and animal. Each organism exhibits, within a short 

 space of time, a series of changes which, when sup- 

 posed to occupy a period indefinitely great and to 

 go on in various ways instead of one, may give us 

 a tolerably clear conception of organic evolution in 

 general. In an individual development we have com- 

 pressed into a comparatively infinitesimal space a 

 series of metamorphoses equally vast with those 

 which the hypothesis of evolution assumes to have 

 taken place during those unmeasurable epochs that 

 the earth's crust tells us of. A tree differs from a 

 seed immeasurably in every respect in bulk, in 

 structure, in colour, in form, in specific gravity, in 

 chemical composition : differs so greatly that no 

 visible resemblance of any kind can be pointed out 

 between them. Yet is the one changed in the 

 course of a few years into the other ; changed so 

 gradually that at no moment can it be said, 'Now 

 the seed ceases to be and the tree exists/ What 

 can be more widely contrasted than a newly-born 

 child and the small gelatinous spherule constituting 

 the human ovum ? The infant is so complex in 

 structure that a cyclopaedia is needed to describe its 

 constituent parts. The germinal vesicle is so simple 

 "Principles of Biology," 118. 



