NEW CONCEPTIONS IN SCIENCE 



a struggle, so to speak, between the two; that in 

 some sense, as Professor Loeb once remarked, death 

 is a physical agent, the material antithesis of life. 

 If the action of the malt enzyme upon starch is 

 reversible, so is that of the ferments which convert 

 the active tissue, the living protoplasm, into the 

 relatively dead, fatty, or connective, or cartilage, or 

 bone tissue the characteristic, as the great Rus- 

 sian biologist, Metchnikoff, has shown, of advanc- 

 ing years. As the discovery of the constructive 

 ferments gave at last a clew to a complete account 

 of the whole life process, so those who have closely 

 and reflectively followed the development of bio- 

 chemistry feel the discovery of reversibility in fer- 

 mentation may in time disclose the reversibility of 

 the life process: in more concrete phrase, the ar- 

 rest of death, the prevention of old age, the preser- 

 vation of youth. 



ON THE NUMBER OF MOLECULES IN THE 

 LIVER-CELL 



It was set down by the philosopher Kant that the devel- 

 opment of a science may be gauged by the amount of 

 mathematics it contains. Probably mere dimensional 

 statistics were not the sort of mathematics Kant had in 

 mind; nevertheless, numerical calculations help wonder- 

 fully to clear thinking, and clear-headed people always 

 make them if they can. They help to visualize a subject. 



It may be of interest, therefore, to make some sort of 

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