SPECIFIC FERMENTS OF THE CANCER CELL 417 



It is well known, however, that all unicellular forms of life 

 contain ferments which it is safe to divide into two classes. 

 These we would designate as soluble and insoluble, or extra- 

 and intracellular ferments; a soluble ferment being one 

 that is excreted by the cell and which performs its ferment 

 action without the cell, and an insoluble ferment being an 

 enzyme that acts only within the cell structure. Obviously, 

 with our rather limited comprehension of the nature of 

 ferments, our knowledge is confined chiefly to the soluble 

 variety. In this class of ferments formed by unicellular 

 organisms might be mentioned zymase formed by the 

 yeast cell, and the putrefactive ferments formed by many 

 bacteria. V. C. Vaughan would also classify such sub- 

 stances as diphtheria toxin and tetanus toxin in this group, 

 since it is his belief that these substances are not poisons 

 in themselves, but liberate poisons through their ferment 

 action. 



While the known functions of most enzymes are those of 

 decomposition, either through such processes as hydrolyza- 

 tion or oxidation, yet we also know that ferment action 

 may be one of construction; and both processes may be 

 carried on by one and the same ferment. Thus we know that 

 ethyl butyrate may be converted by the action of lipase 

 into alcohol and butyric acid, while with a change in the 

 acting masses, alcohol and butyric acid plus lipase will 

 form the ester. 



Inasmuch as we do know of the presence of constructive 

 ferments belonging to the soluble variety, in which class 

 we would naturally suppose the greater number to be 

 destructive, since their function is to reduce complex 

 proteins into simpler forms for the easier assimilation by 

 the cell, it seems reasonable to suppose that most intra- 

 cellular or insoluble ferments are of the constructive variety, 

 and that it is through their aid that simple chemical sub- 

 stances are converted into the complex distinctive proteins 

 of the cell itself. 



While much of the above is theoretical, yet there is 

 sufficient knowledge concerning some of the facts to make 

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