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 credi 

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

 Darwin's own subsequent remark respecting the domestic rabbit 

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

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

 continued selection of the heaviest individuals, the weight 

 the larger breeds has been more than doubled." Obvious! 

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

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

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

 third place, as certainly it should. 



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

 thus : By the continued supply of abundant and highly nutritio 

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

 the organism becomes pathologically increased. By makin 

 exploitatory use of the principle of compensation, man indue 

 a hypertrophy in some parts together with an atrophy in othe 

 By the destruction of those animals which lend themselves le 

 to man's exploitatory purposes, the. abnormality of the survive 

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

 except for some mitigating circumstances, is one of systemati 

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

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

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

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

 never quite clear about the physiological part of the theory 

 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 " Cont re-Evolution." 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 



