378 THE EVOLUTION THEORY 



the species. By this means germinal selection itself is ultimately 

 influenced, because only those ids remain unrejected in the germ-plasm 

 whose determinants are varying in directions useful to the species. 

 Thus there comes about what until recently was believed to be 

 impossible : the conditions of life give rise to useful directions of 

 variation, not directly, certainly, but indirectly. 



We may distinguish as a fourth grade of selection Cormal 

 Selection, that is, the process of selection which effects the adaptation 

 of animal and plant stocks or corms, and which depends on the 

 struggle of the colonies among themselves. This diflfers from personal 

 selection only in that it decides, not the fitness of the individual 

 person, but that of the stock as a whole. It is a matter of 

 indifference whether the stocks concerned are stocks in the actual 

 material sense, or only in the metaphorical sense of sharing the 

 common life of a large family separated by division of labour. In 

 both cases, in the polyp-stock as well as in the termite or ant-colony, 

 the collective germ-plasm, with all its different personal forms, is what 

 is rejected or accepted. The distinction between this cormal selection 

 and personal selection is, therefore, no very deep one, because here 

 too it is in the long run the two sexual animals which are selected, 

 not indeed only in reference to their visible features, but also in 

 reference to their invisible characters, those, namely, which deter- 

 mine in their germ-plasm the constitution of their neuter progeny 

 or, in the case of polyps, their asexually reproducing descendants. 



We venture to maintain that everything in the world of 

 organisms that has permanence and significance depends upon 

 adaptation, and has arisen through a sifting of the variations which 

 presented themselves, that is, tlirough selection. Everything is 

 adaptation, from the smallest and simplest up to the largest and 

 most complex, for if it were not it could not endure, but would 

 perish. The principle Avhich Empedocles announced, in his own 

 peculiar and fantastic way, is the dominating one, and I must insist 

 upon what has so often been objected to as an exaggeration — that 

 everything depends upon adaptation and is governed by processes of 

 selection. From the first beginnings of life, up to its highest point, 

 only what is purposeful has arisen, because the living units at every 

 grade are continually being sifted according to their utility, and the 

 ceaseless struggle for existence is continually producing and favouring 

 the fittest. Upon this depends not only the infinite diversity of the 

 forms of life, but also, and chiefly, the closely associated progress of 

 organization. 



It cannot be proved in regard to each individual case, but it can 



