n6 SYMBIOSIS 



poison " provides the best key to an understanding of " modi- 

 fication " and species-formation. Variations, he says, are pro- 

 bably less blind than we think, "if we could know the whole 

 truth," and he proceeds to connect the trend of variations with 

 the gradual growth of " organic wealth " through work. Limbs 

 or instincts, all alike, he would but regard as the things that 

 organisms " have bought with their money, or with money that 

 has been left them by their forefathers, which, though it is 

 neither silver, nor gold, but faith and protoplasm only, is good 

 money and capital notwithstanding." 



Butler does not think that the desire of the organism is the 

 sole cause of variations, but, in a passage which may be regarded 

 as an attempt at a blend of Lamarckism with Darwinism, he 

 suggests that there is a mutual determination of some sort between 

 organism and "environment." He admits readily that 



The common course of nature would both cause many variations to arise 

 independently of any desire on the part of the animal and would also 

 preserve and accumulate such variations when they had arisen. But 

 (he goes on to say), I can no more believe that the wonderful adaptation 

 of structure to needs, which we see around us in such an infinite number 

 of plants and animals, can have arisen without a perception of those needs 

 on the part of the creature in whom the structure appears, than T can 

 believe that the form of the dray-horse or greyhound so well adapted 

 both to the needs of the animal in his daily service to man and to the 

 desires of man, that the creature should do him this daily service can 

 have arisen without any desire on man's part to produce this particular 

 structure, or without the inherited habit of performing the corresponding 

 actions for man, on the part of the greyhound and dray-horse. 



There is then something of importance attributable to the 

 " common course of nature " whatever this course may be. 

 This something operates over and above volition, over and above 

 memory although it is not unconnected with either. I think it 

 is now evident that Symbiosis with its momenta provides the best 

 clue to an understanding of the mysterious influence, not dis- 

 sociable from volition and memory, yet inherent in the " common 

 course of nature." It is in Symbiogenesis that I believe we have 

 an explanation of the way in which the tendencies of the organism 

 are being made use of in the preservation and accumulation of 

 variations in accordance with their merits. We can believe this 

 without having in any way to deny the concurrence of mind and 

 of volition on the part of tho organism. How otherwise puzzling 

 the subject of variations remains may best be seen from a 



