105 BENEFICIAL ACTION OF CERTAIN "POISONS"; AND 



well known. Dr. Creighton and I found it fairly poisonous 

 for hepatic reductase: when the normal liver (cat) needed 

 ten minutes to reduce diluted blood, the addition of 0.01 

 normal HgCl2 prolonged the time to 17 minutes. Waller 

 and others have shown the high toxicity of HgCl2 for ptyalin 

 and for pepsin, both exo-enzymes. Mercuric chloride is 

 therefore poisonous not only for the biogens, but also for 

 their products, the enzymes which remain in the cells as well 

 as for those which leave them. 



Another poison HON or KCN has been examined in 

 regard to this threefold conception of the vital machinery. 

 Its toxicity for the entire organism is notorious. Dr. Creigh- 

 ton and I found it very poisonous towards hepatic reductase; 

 it added 24 minutes to the time (10 minutes) for the reduction 

 of the blood by unpoisoned liver juice. Mr. J. B. Reed° 

 found 1% KCN destroyed all the oxidase (for indo-phenol) 

 in vegetable cells; he further found that the ventral nerve- 

 cord of crawfish after treatment with KCN was quite unable 

 to exhibit any oxidizing power. KCN also prevented any 

 oxidase activity on the part of the leycocytes of human blood. 

 But KCN, except in very high concentration, does not affect 

 the activity of pepsin. KCN is therefore highly toxic to- 

 wards living matter and towards both the reducing and oxidiz- 

 ing endo-enzymes, but not towards secretion-enzj-mes. 



Another substance poisonous for protoplasm and endo- 

 enzyme, but not for secretion-enzyme is arsenious acid 

 (AS2O3). It is highly toxic for naked protoplasm. Dr. Creighton 

 and I found it added 23 minutes to the time (10 minutes) 

 for hepatic reductase to reduce blood. It was used in 0.01 

 normal concentration. But against pepsin it has little 

 power except in very high concentration. Ether for instance, 

 does not inhibit the action of lipase. 



°Th(' role of oxidiusos in resi)iration. J. B. Reed, .11. Biol. CliiMii. Au^. 1915. 



