INTEODUCTION 17 



elimination starts immediately after absorption. This is 

 especially true for volatile poisons like hydrocyanic acid, 

 alcohol, and the like, which are eliminated in great propor- 

 tion by the lungs. 



All the excretory channels are concerned in elimination, 

 but the most important in this respect are the kidneys. 

 The milk is a less important channel of elimination. The 

 skin also plays a part, and the beneficial effects of drugs are 

 in many cases attributable to their local excretion — e.g., of 

 balsams through the lungs, and of arsenic through the 

 skin. 



The time taken in elimination varies very greatly, is 

 most rapid with volatile agents, and generally is quicker 

 after injection than after ingestion. 



An instructive and important example regarding arsenic 

 is given by Taylor. The maximum of arsenic in the liver 

 was attained in fifteen hours after ingestion, viz., 2 grains 

 to 3^ pounds ; after fourteen days the proportion was 0"17 ; 

 and after seventeen days nil (Geoghegan). Valuable as 

 such data are, they must on no account be taken to be 

 general and precise. They only serve to illustrate the 

 relative speed of elimination, which, in a given case, will be 

 modified by such factors as dosage, condition of the subject, 

 and other circumstances. 



VARIATIONS OF ACTION DUE TO SPECIES. 



Wide differences in reaction towards a given poison 

 are noticed in comparing the various species with one 

 another. In part these variations are explicable on 

 anatomical and physiological grounds, though by no means 

 always. The differences in the digestive apparatus and 

 in the nervous system serve to account for some variations. 

 In ruminants ingested poison is immensely diluted in the 

 rumen, is distributed evenly on rumination, and in general 

 is absorbed more slowly than in the horse or carnivore. 

 This affords greater opportunity for elimination, and 



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