82 CONTEMPORARY SCIENCE 



of these products is 100 per cent, pure has been advanced, 

 and the chemist through bitter experience knows the dan- 

 ger in discussing the composition of impure substances. 

 Another fact to be kept in mind is that, often enough, 

 the purer the enzyme, the less active does it become. In 

 several of these cases it has been shown that a loss in 

 activity goes hand in hand with a proportional loss in the 

 phosphoric acid content of the substance. This gives rise 

 to the possibility expounded further on that the enzyme 

 is not a chemical individual, but consists of at least two 

 substances: (a) a something which has the power of act- 

 ing only when activated in this instance by (b) phos- 

 phoric acid. And yet, if arguing by analogy is at all 

 permissible, it may be maintained that since all the in- 

 organic catalysts are distinct chemical individuals, why 

 not enzymes ? 



Of course, all this does not at all exclude the possibility 

 that different enzymes may have different structures and 

 the conflicting results of investigators may be due to this 

 fact. Some of the men worked on amylases (starch-split- 

 ting enzymes), others on lipases (fat-splitting), others 

 still on proteases (protein-splitting). Why assume that 

 such diverse substances should all have the identical com- 

 position? It may be, as Professor Armstrong has sug- 

 gested, that the enzyme in constitution is similar to the 

 substance on which it acts. 



Extremely suggestive as the basis for much present-day 

 activity has been the work of Professor Gabriel Bertrand, 

 of the Sorbonne, Paris. Most of this has been on laccase, 

 an oxidizing enzyme first found in the milky latex of the 

 tree Rhus vernicifera, and since then in many plants. The 

 production of the beautiful Japanese lacquer from the 

 latex of Rhus vernicifera was shown to be due to the 

 activation of the atmospheric oxygen by the laccase 

 (hence its name). Bertrand was able to prove that the 

 activity of the laccase was connected with the manganese 

 present, for by repeated precipitation with alcohol, he di- 



