BIONOMICS 193 



hormones and vitamines, substances which though present in 

 but minute amounts, yet by their molecular constitution 

 their symbiogenetic character are capable of producing 

 most wonderful and most important effects upon organic 

 matter. Nay, more, they seem to contain the most indis- 

 pensable guiding principles influencing organic form. The 

 absence of "vitamines" in food, as we have seen, is easily 

 fatal because leading to " deficiency-diseases." It is due 

 to the presence, again, of adequate bio-chemical stimulation 

 that such important glands as the corpus luteum and the 

 thyroid are able to perform their vital and indispensable 

 functions. The very word " bio-chemical " proclaims that life 

 itself, in its efforts to solve the economic problem, we may 

 presume, gives rise to these substances. They appear 

 originally as bye-products of the photo-synthetic and 

 associated metabolic processes of the plant, which processes, 

 just as they imply a storage of material for future 

 bio-economic use, so also in a subtle way impress symbio- 

 genetic momentum upon these highly complex and delicately 

 poised substances. Bio-chemical substances are thus 

 essentially bio-economic substances, and, like organs, owe 

 their efficacy to symbiogenetic processes. Enzymes have been 

 termed the tools of cells. Their number is legion ; but 

 Chemistry cannot produce them. They are found only as the 

 products of protoplasm of living cells and are known only by 

 their reactions "by their works ye shall know them." They 

 are found in association with proteins. Mineral salts, how- 

 ever, seem essential for their action, which would seem to 

 indicate the primordial connection with cross-feeding on the 

 part of the strenuous vegetable or plant-animal cell. 



In Spencer's day, of course, an adequate computation of 

 food-components was out of the question. Nevertheless 

 Catalysis was known to him, and with his usual acumen and 

 circumspection he points out that " there is great reason for 

 thinking that to this kind of action is due a large amount of 

 vital metamorphosis." 



