104 BENEFICIAL ACTION OF CERTAIN "POISONS"; AND 



tine. Our inference once again was that the deadly alkaloidal 

 narcotics do not compromise life by interfering seriously 

 with the inspiratory phase of tissue-respiration. But if 

 this be admitted, then the deadly narcotics must be assumed 

 to act on the living molecules of bioplasm, the biogens them- 

 selves. The deadly character of the narcotic alkaloids is 

 exerted not on any substance in the outer sphere of influence 

 of the bioplasm, not even on the endo-enzyme of tissue res- 

 piration, but on the very centre and citadel of life itself. 

 Doubtless this is much as we should have expected a priori; 

 and some critic may remark that it is not throwing much 

 fresh light on protoplasmic poisons; but it at least tells us 

 where the toxicity of alkaloids does not preeminently exert its 

 power. This may not be much by itself, but it clears the 

 ground for the next inquiry, namely: 



What is it in the biogen for which the alkaloid has af- 

 finity, what is it precisely that is immobilized in fatal poisoning? 



The poisonous action of alcohol on the lowliest forms of 

 life is well brought out in a set of curious experiments by 

 Professor Woodhead of the University of Cambridge. Us- 

 ing plate-cultures of the phosphorescent bacillus of Byer- 

 inck, he actually contrived to photograph the light produced 

 by it in a twenty minutes' exposure. When 7 to 12 per cent, 

 of alcohol was introduced into the culture, the light was 

 abolished altogether; when 5% was introduced, the exposure 

 required was 2.5 hours to obtain the same depth of result 

 as was given by the unpoisoned bacilli in twenty minutes. 

 Here we may say we have the toxic power exerted on the 

 organism as a whole, for we may not in all cases of plants be 

 able to discriminate between protoplasm and enzyme. 



In certain animals which produce light, for instance the 

 fire-fly, Photinus pyralis, the light production has actually 

 been attributed to a ferment luciferase an oxidase carrying 

 oxygen to a substance luciferin. It is claimed that these sub- 

 stances can be separated; each alone produces no light. whereas 



