118 THE INDUCTIONS OF BIOLOGY. 



X. 



exceptions, are, by the conditions of their existence, required 

 to take in nutriment through one specialized part of the 

 body, it is clear that there must be a means whereby other 

 parts of the body, to be supported by this nutriment, must 

 have it conveyed to them. It is clear that for an equally 

 efficient maintenance of their nutrition, the parts of a large 

 mass must have a more elaborate propelling and conducting 

 apparatus ; and that in proportion as these parts undergo 

 greater waste, a yet higher development of the vascular 

 system is necessitated. Similarly with the pre-requisites to 

 those mechanical motions which animals are required to 

 perform. The parts of a mass cannot be made to move, and 

 have their movements so co-ordinated as to produce locomo- 

 tive and other actions, without certain structural arrange- 

 ments ; and, other things equal, a given amount of such 

 activity requires more involved structural arrangements in a 

 large mass than in a small one. There must at least be a 

 co-ordinating apparatus presenting greater contrasts in its 

 central and peripheral parts. 



The qualified dependence of growth on organization, is 

 equally implied when we study it in connexion with that 

 adjustment of inner to outer relations which constitutes LitV. 

 In plants this is not conspicuous, because the adjustment of 

 inner to outer relations is but small. Still, it is visible in tl e 

 fact that the condition on which only a plant can grow to a 

 great size, is, that it shall, by the development of a massive 

 trunk, present inner relations of forces fitted to counter- 

 balance those outer relations of forces, which tend continually 

 and occasionally to overthrow it ; and this formation of a 

 core of regularly- arranged woody fibres, is an advance in 

 organization. Throughout the animal kingdom, this 



connexion of phenomena is manifest. To obtain materials for 

 growth ; to avoid injuries, which interfere with growth ; am? 

 to escape those enemies which bring growth to a sudden end ; 

 implies in the organism, the means of fitting its movements 

 to meet numerous external co-existences and sequences 



