THE LIVING SUBSTANCE. 159 



history ; some initiative characters one day to mark a new 

 species — incidental but potent beginnings ; some dying 

 results of exhausted or unused opportunities ; some products 

 of an overloaded, overstimulated state which will suffer read- 

 justment ; — any of these things each may be. Whether an 

 evanescent possibility, or initiative of some new series of fruit- 

 ful structural deviations, whether to be used by the substance 

 as a physical lever, a chemical cause, or perhaps as a mere 

 storehouse of opportunities, or prison for adverse or detri- 

 mental influences ; — such is in each case, and in each moment 

 with respect to the same vesicular structure, our problem. 

 One may be watching the last falling leaf of some great tree 

 of biological sequence, or the forming of embryonic leaf and 

 root of another such. The organism would seem to be more 

 than we have thought it and less than we have taken it to be. 

 It is an incident rather than an end, but as incident far more 

 marvellous and comprehensible than as prime end. A most 

 complex and compound race organ, it represents a recurrent 

 grouping of substance habits as to local deposit of material 

 and local relations with these. Of such are formed all like- 

 nesses of character between organisms and their grosser 

 structures ; likewise all differences whether of individual, 

 species, genus, family or race. But within the limits of the 

 most closely resembling descendants there is room for enor- 

 mous variation, as well as of mere diversity of substance 

 organs, both as to their extension and complexity, without pos- 

 sibility of our detection as yet. Possibly in many cases with- 

 out any essential difference resulting. This is, it seems to me, 

 a most natural result of the mode of organization and growth. 

 Of such of these variations as best fall in with the opportuni- 

 ties of the organism as race organ and race substance, of such 

 as least interfere with, are most closely allied to, or most in 

 harmony with, established tendencies of race rhythms as well 

 as those of the individual, with latent as well as with patent 

 lines of substance phenomena ; grosser variations will probably 

 be built up. For thus, it seems to me, natural selection must 

 act. As substance organs arising from mere physical incident 

 can become true mass organs, so the organism arising from 



