33 THE DATA OF BIOLOGY. 



organism. Similarly with the heterogeneity of the changes. 

 In the environment the relations are very varied in their 

 kinds ; and hence, as the organic actions come more and more 

 into correspondence with them, they also must become very 

 varied in their kinds. So again is it, even with definiteness 

 of combination. For though the inorganic bodies of which 

 the environment mainly consists, do not present definitely- 

 combined changes, yet they present definitely-combined 

 properties ; and though the minor meteorologic variations of 

 the environment, do not show much definiteness of combination, 

 yet those resulting from day and night and the seasons do. 

 Add to which, that as the environment of each organism 

 comprehends all those other organisms existing within its 

 sphere of life — as the most important and most numerous 

 surrounding changes with which each animal has to deal, 

 are the definitely-combined changes exhibited by other 

 animals, whether prey or enemies ; it results that definiteness 

 of combination is a general characteristic of the external 

 changes with which internal ones have to correspond. Hence, 

 increase of correspondence involves increased definiteness of 

 combination. So that throughout, the correspondence of 

 the internal relations with the external ones, is the essential 

 thing ; and all the special characteristics of the internal 

 relations, are but the collateral results of this correspondence. 



§ 35. As affording the simplest and most conclusive proof 

 that the degree of life varies as the degree of correspondence, 

 it remains to point out that perfect correspondence would be 

 perfect life. Were there no ohanges in the environment but 

 such as the organism had adapted changes to meet ; and were 

 it never to fail in the efficiency with which it met them ; there 

 would be eternal existence and universal knowledge. Death 

 by natural decay, occurs because in old age the relations be- 

 tween assimilation, oxidation, and genesis of force going on 

 in the organism, gradually fall out of correspondence with the 

 relations between oxygen and food and absorption of heat by 



