200 SYMBIOSIS 



these modifications appertain to the pathological order and are 

 the opposites of those produced in normal evolution. The 

 modifications under Domestication redound little to the credit 

 of " Selection." Justification for this view is again afforded by 

 Darwin's own subsequent remark respecting the domestic rabbits, 

 concerning which he tells us (p. 157) : " By the supply of abundant 

 and nutritious food, together with little exercise, and by the 

 continued selection of the heaviest individuals, the weight of 

 the larger breeds has been more than doubled." Obviously 

 Darwin felt constrained, by the force of the evidence, to give 

 pride of place to two positive factors, namely (a) food, and (b) 

 exercise, whilst the negative factor : destruction (selection^ takes 

 third place, as certainly it should. 



Supposing, in the place of Darwin's phrasing, we put the case 

 thus : By the continued supply of abundant and highly nutritious 

 but unnatural food, together with too little exercise, the size of 

 the organism becomes pathologically increased. By making 

 exploitatory use of the principle of compensation, man induces 

 a hypertrophy in some parts together with an atrophy in others. 

 By the destruction of those animals which lend themselves least 

 to man's exploitatory purposes, the abnormality of the survivors 

 (the " selected ") tends even to be increased. The whole process, 

 except for some mitigating circumstances, is one of systematic, 

 non-symbiotic and semi-parasitic exploitation, which cannot but 

 be physiologically injurious, i.e., it is pathological in effects. The 

 term " Selection," therefore, fails to convey what is chiefly 

 entailed in Domestication. " Darwin," says De Vries, " was 

 never quite clear about the physiological part of the theory of 

 Selection." 



But who amongst recent writers sees clear in these matters ? 

 Who has shown that physiology is above all determined by 

 biological behaviour ? 



But to return now to " Contre-E volution." It is when we 

 come to Dr. Larger's treatment of the aetiology of " Gigantisme 

 acromegalique " that we are afforded the utmost justification 

 for concluding that surfeit and in-feeding are largely responsible 

 for the implied Pathogenesis. Frequently the abnormalities, 

 atrophies, precocities and disharmonies are quite obviously of 

 the same character as those occurring in Domestication, or, still 

 more so, in rank Parasitism. There is, first of all, the case of 

 some giant tadpoles, discussed at considerable length by Dr. Larger 



