106 SYMBIOGENESIS 



due to the exceptional non-fulfilment of those conditions which 

 entail limitation. What kind of life does a crocodile lead"? 



Spencer here, indeed, puts the most pertinent question 

 concerning the conditions of growth, and he implies, or rather 

 concedes, that there may be exceptional (abnormal) habits of 

 life calculated to set at nought such wholesome restraints and 

 checks of bulk, incidental upon symbiotic activity, as we find 

 to be the rule amongst normal organisms. This belated recog- 

 nition, however, he uses too little and nowhere to the extent 

 which it deserves. 



What kind of life, indeed, does a crocodile lead? 



This cold-blooded, or almost cold-blooded creature, he tells 

 us, will not even undergo much exertion in catching its prey. 

 Consequently it expends very little for the maintenance of 

 heat. In short, " the mechanical causes necessitating a limit 

 are here only partially in action." And thus, as is usual with 

 Spencer, instead of an inquiry into the significance of habits, 

 the whole matter is considered on purely mechanical 

 grounds, although quite obviously they offer but a fractional 

 explanation of the phenomena concerned. " The exceptional 

 continuance of growth observed in creatures so circumstanced 

 (?) is therefore perfectly explicable." 



But though abnormally increasing bulk may have its rela- 

 tions, in Spencerian parlance, to "gravitational forces," and 

 also to powers that increase as the " cubes of dimensions," it 

 must also have important relations with other developments, 

 it must be associated also with definite qualitative physio- 

 logical or pathological, with bio-economic and psychological 

 changes. As regards these important relations, however, 

 Spencer is silent. Nor was the importance of symbiosis 

 apparent enough in his days to permit of a proper analytical 

 method of dealing with the dynamics of growth. 



Let us now take some concrete cases of the practical utilisa- 

 tion of positive ancestral dynamics. And, first, as to the 

 significance of " grafting." 



