LIFE AND HABIT 117 



statement by Geddes and Thomson in their little work on 

 Evolution (pp. 141, 142). They tell us that it is quite impossible 

 at present to say how variations arise. 



We know very little, they say, that is certain in regard to the origina- 

 ting factors in evolution. We must still confess, with Darwin : " Our 

 ignorance of the laws of variation is profound." 



Weismann has suggested that the oscillations and changes in the 

 blood and other nutritive fluids may stimulate the germ-plasm to a new 

 departure. It may also be that important changes in the environment 

 may saturate through the body and provoke the germ -plasm to vary. 

 There are other " may be's." 



The suggestions thus thrown out are not antagonistic to the 

 symbiogenetic view. It is only necessary to realise the quasi- 

 genetic value of food and its role as mediator between organism 

 and the environment in order to understand how the symbio- 

 genetic and symbio -psychic complex of life produces an urge 

 consistent only with the highest good of the organic world, which 

 urge is enough to call forth and to direct variations as required 

 in the normal course of life. 



After telling us that Lamarck's theory fell into disrepute, 

 partly because his ideas were too startling to be capable of ready 

 fusion with existing ideas, Butler asserts that the main cause 

 of evolution must be looked for, as Lamarck insisted, in the 

 needs and experiences of the creatures varying, and in this 

 connection he attacks once more the problem of Variation 

 thus : 



Unless we can explain the origin of variations, we are met by the 

 unexpected at every step in the progress of a creature from its original 

 homogeneous condition to its differentiation, we will say, as an elephant ; 

 so that to say that an elephant has become an elephant through the 

 accumulation of vast numbers of small, fortuitous, but unexplained, 

 variations in some lower creatures, is really to say that it has become an 

 elephant owing to a series of causes about which we know nothing whatever, 

 or, in other words, that one does not know how it came to be an elephant. 

 But to say that an elephant has become an elephant owing to a series of 

 variations, nine-tenths of which were caused by the wishes of the creature, 

 or creatures from which the elephant is descended this is to offer a reason, 

 and definitely put the insoluble one step further back. 



A good beginning towards explaining the origin of variations 

 is undoubtedly made by pointing to the volition of the original 

 creature. But it is only a beginning, and it does not go far 

 enough. 



It is well to go back for a clue to the " original creature " ; 

 but the volition and interests of one organism are constantly 



