464 PHYSIOLOGICAL REGULATIONS 



than Qx, §21 etc. would be. Leaving the assumption of advantage 

 out of account, I suggest that adaptation is the pattern of modifi- 

 cations already noted in equilibrations, and that those interrela- 

 tions are directly measured by loads, rates, and their correlatives. 



Experimentally it might be possible to set up criteria by which 

 to test whether state H, and all that goes with it, more often leads 

 to recovery, or to survival, than state G; or whether the combina- 

 tion of gx, Oil etc. with H would favor it. Another criterion of sur- 

 vival, or some entirely different criterion, often gives a different 

 answer. 



Indirect equilibration, according to Spencer, is gradual varia- 

 tion in a property of the organism or genotype while it is meeting 

 situations that are unlike, in intensity or recurrence, those to which 

 it formerly was exposed. I suppose one could hardly distinguish 

 where the changes coincident with the first equilibration ended and 

 those coincident with the second began. When a modification 

 occurs in a future generation, it too is measured as a rate of ex- 

 change and not as a force. 



Driesch ('08), also, attempted to distinguish between regula- 

 tions that are already prepared (adaptedness) and regulations that 

 come into existence when state H arises. I find no criterion of 

 preparedness that is concise. He also suggests that functional 

 disturbances are distinct from structural disturbances, a classifi- 

 cation that I find difficult to use. I suggest that only quantitative 

 categories are practical, particularly when like Driesch one is try- 

 ing to separate the abnormal from the normal. 



The differentiation between direct and indirect equilibration 

 perhaps corresponds to the diversities of physiological and corre- 

 lated ecological patterns encountered in the deer mice of Ross (see 

 §98). Rates of water turnover and preferences of environment 

 were significantly different in two species, but not in two subspecies 

 of either one of them. Conditioning, even lasting more than one 

 generation, did not abolish the difference. The correlations were 

 of a sort that were thought to favor survival in each of the environ- 

 ments ordinarily selected. The environmental equalization evi- 

 dently induced no shift in water turnover, for that was stabilized 

 by internal interactions (direct equilibration) to a degree that 

 allowed of no external influence. 



Every equilibration, even an unprepared one, represents pro- 

 visions for contingencies. Whether it also is a ^^^evision can only 



