292 THE WORLD OF LIFE 



Germinal Selection 



The numerous and varied phenomena which have been 

 merely sketched in outline in the present chapter receive an 

 approximate explanation by Professor Weismann's theory of 

 germinal selection, which he first published in 1896. He 

 appears to have been led to it by feeling the difficulty of ex- 

 plaining many of these phenomena by the ^' natural selection " 

 of Darwin; but to have laid more stress on those of Section 2 

 of the present chapter than those of Section 3. He had in 

 1892 published his elaborate volume on The Germ-Plasm a 

 Theory of Heredity, to which this later theory is a logical 

 sequel. 



During the last quarter of a century many striking discov- 

 eries have been made in what may be termed the mechanism 

 of growth and reproduction ; each successive advance in micro- 

 scopic power and methods of observation have brought to light 

 whole worlds of complex structure and purposive transfor- 

 mations in w^hat was before looked upon as structureless cells 

 or corpuscles. Some attempt will be made in a later chapter 

 to discuss these primary life-phenomena; here it is only neces- 

 sary to show briefly how Weismann's new theory helps us to 

 understand the facts of life-development we have been dealing 

 with. For this purpose I cannot do better than quote Pro- 

 fessor Lloyd Morgan's very clear statement of the theory. 

 He says : ^ 



" The additional factor which Dr. Weismann suggests is what 

 he terms ^ germinal selection.' This, briefly stated, is as follows : — 

 There is a competition for nutriment among those parts of the germ 

 named determinants, from which the several organs or groups of 

 organs are developed. In this competition the stronger deter- 

 minants get the best of it, and are further developed at the expense 

 of the weaker determinants, which are starved, and tend to dwin- 

 dle and eventually disappear. The suggestion is interestingj but 

 one well-nigh impossible to test by observation. If accepted as a 



1 Habit and Instinct, p. 310. 



