^64 



ACTION OF POISONS ON THE ANIMAL SYSTEM. 



deathj 1 have never, in any one instance, been able to pro- 

 long its action by means of artificial respiration. 3, pain in 

 the region of the abdomen ; preternatural secretion of mucus 

 from the alimentary canal ; sickness and vomiting in those 

 animals which are capable of vomiting; symptoms which arise 

 from the action oi the poison on the stomach and intestines. 

 There is no difference in the effects of arsenic, whether it is 

 employed in the form of white oxide, or of arsenic acid, except 



Arsenic ap. that the latter is a more active preparation. When arsenic is 

 P"«d to ,. , , , , , , 



wounds acts applied to a wound, the symptoms take place sooner than 



most speedily, when it is given internally j but their nature is the same. 



EfFects of arse- jjjq symptoms produced by arsenic may be referred to the 

 influence of the poison on the nervous system, the heart*, and 

 the alimentary canal. As of these the two former only are 

 concerned in those functions which are directly necessary to 

 life, and as the alimentary canal is often affected only in a 

 slight degree, we must consider the affection of the heart and 

 nervous system as being the immediate cause of death. 



In every experiment which I have made with arsenic, there 

 Vv'ere evident marks of the influence of the poison on all the 

 organs which have been mentioned ; but they were not in all 

 cases affected in the same relative degree. In the dog, the 

 affection of the heart appeared to predominate over that of the 

 brain, and on examining the thorax immediately after death, 

 this organ was found to have ceased acting, and in a distended 

 state. In the rabbit, the affection of the brain appeared to 

 predominate over that of the heart, and the latter was usually 



The heart in * When I say, that a poison acts on the heart, I do not mean to imply, 



some respect that it necessarily must act directly on the muscular fibres of that organ. 



jndepeRdent It is highly probable, that the heart is affected only through the medhim 



fectfo"^ f V °^ ^"^^ nerves; but the affection of the heart is so far independent of the 



nervous sv- affection of the nervous system generally, that the circulation may cease 



jem. although the functions of the brain are not suspended, and ihe functions 



of thcbrain may be \'5holly suspended without the circulation being at 



all disturbed, in proof of the first of these propositions, I may refer to 



my former experiments on the upas antiar, in which the seiisibility of 



the animal continued to the very instant of death ; and respiration, 



which is under the influence of the brain, continued even after the heart 



had ceased to act. In proof of the second, I may refer, among many 



others, to the experiments detailed in the Croonian Lecture for 1810. — 



{Phil. Trans, for 1811, pp. .Se, 211 ; pr Journal, vol. XXIX, p. 359.] 



found 



