64 Causes and Course of Organic Evolution 



treated. Similarly, if any one group of molecules in a living 

 structure be altered even to the minutest chemical degree in 

 one out of many of its constituents, such must confer new 

 specificity on the structure itself. 



Just as in inorganic and organic compounds, then, to which 

 the chemist has applied exact names, these remain stable 

 and are acted on and react precisely, so long as they are exposed 

 within like physico-chemical limits or environment, so for 

 living bodies — highly complex and delicately equilibrated 

 though their molecules may be — each within precise physico- 

 chemical limits is recognized by a specific name, that connotes 

 it as truly as does the name given by the chemist for each sub- 

 stance. 



It will readily be seen, however, that, even with only 10,000 

 to 20,000 possible combinations on which to work, the capacity 

 which plants and animals possess for linking-up combinations 

 or for decomposition actions is practically endless. But, while 

 such is largely true, we hope to show in a future chapter that 

 the supposed limitless variations which some evolutionists have 

 considered that organisms possess are after all fairly restricted, 

 and work along certain fairly exact grooves. 



Reference has already been made (p. 63) to the steadily 

 increasing list of "organic" compounds which the chemist has 

 been able to synthesize. The list is an imposing one if note 

 be made only of the synthesis of a certain compound from a 

 simpler one that is also of organic origin. But, if one select 

 those only which have been built up step by step from what 

 were inorganic compounds to start with, the list becomes 

 reduced to small proportions. Furthermore, practically all of 

 those synthesized are crystalloids, and colloids are conspicu- 

 ously absent from the list. Thus, to select one from many 

 cases, while several of the sugars have been built up from 

 simpler bodies, neither vegetable starch nor cellulose, both of 

 them abundant and typical plant colloids, has been so produced. 



If one take note further of the laboratory means employed, 

 to effect synthesis of the organic crystalloids already secured, 

 one is impressed by the elaborate expenditures of either thermic. 



