INFLUENCES OF POISON ON PROTOPLASM, KTC. IIAHKIS. 105 



the intraction of the two does so. It is tluM-ctore {;on('(Mval)l(; 

 that the toxicity of alcohol against liii;lit-production might, 

 in the case of animal bioplasm, be exerted on the enzymes and 

 not on the biogens. 



One of our general conclusions was thus stat:\l; sub- 

 stances which are known to ba rapidly fatal to animals and 

 which depress the vitality of isolated tissuss (muscles, nerves, 

 etc.) that is, are deadly protoplasmic poisons, are not poisons 

 in the same sense for reductase from liver or from l)rain. 

 Another was; substances which are virulent poisons to pro- 

 toplasm (e.g., aconitine, hyoscine hydrobromide) inhibit 

 reductase no more elTectively than substances very much less 

 poisonous to protoplasm, namely, alcohol and caffeine ci- 

 trate. 



We were not prepared for these results; we had expected 

 that such virulent poisons as aconitine, hyoscine and morphine 

 would seriously interfere with tissue respiration. These 

 alkaloids interfere with tissue respiration to a trifling extent 

 compared with what they do as regards putting the vital 

 machinery itself out of action. These deadly poisons com- 

 promise the activity" neither of such separated substances as 

 the secretion-enzymes, nor the non-separated endo-enzymes, 

 but they do interfere in some way not at present understood 

 with the inmost molecular activity of the biogens themselves. 

 They put their enemy out of action, not by destroying his 

 ammunition but by destroying the factories themselves. 

 Yet the various narcotics differ inter se in regard to their 

 toxicity both for neuroplasm and for neural reductase: thus 

 chloroform is about 2.3 times as poisonous as hyoscine to- 

 wards neural reductase. 



Poisons of Bioplasm, of Endo-Enzymes and of Exo-Enzymes. 



Certain poisons for bioplasm are poisons also for both its 

 endo-enzymes and its exo-enzymes; such a substance is 

 mercuric chloride. Its toxicity for the whole organism is 



