40 NATIONAL TRENDS IN BIOLOGY 



D. Keilin's discovery of the cell pigment '^cytochrome," 

 which has something to do with the control of oxygen 

 within the cell also should be mentioned. 



Finally, Professor Baly's discovery of artificial photo- 

 synthesis should not be forgotten. Baly's work made pos- 

 sible the forming of organic compounds, such as formal- 

 dehyde, from water and carbon dioxide, which process, in 

 turn, formed sugar. 



Nearly all biologists placed the work on endocrines 

 among the most notable achievements of this generation. 

 Thomson says of these powerful factors in the lives of 

 all organisms, that they are chemical messengers which are 

 like ''keys that open certain doors and close others, and 

 they exert a regulative action on many of the functions of 

 the body, securing their orchestration or correlation." 



The discovery of this chemical integration "has changed 

 the whole face of physiology. Biologically regarded, the 

 hormones, such as adrenalin and thyroxin, enable the 

 biologist to understand not only everyday events such as 

 the cat's hair standing on end before the intruding dog, 

 but the changes that come in adolescence when hormones 

 from the reproductive organs saturate throughout the 

 body, and activate the growth of the stag's antlers, the 

 swelling of the frog's first finger, and scores of other 

 adolescent novelties." 



The most spectacular work in preventive medicine, 

 which really belongs in this century, because real effective 

 proof of its working out was not forthcoming until 1900 

 or thereafter, is that of the discovery of how malaria and 



