THE SMITHSONIAN INSTITUTION. 129 



was said to be from a sympathetic affection, conveyed in some myste- 

 rious manner by the nerves. 



The statement that any such impression is conveyed is as purely 

 gratuitous as was the explanation of the pressure of the atmosphere by 

 the simple expression, "nature abhors a vacuum." 



Since the experiments of Magendie, in 1809, on the subject of absorp- 

 tion, it has generally been admitted that most poisons produce their 

 effect on the system by being absorbed and carried into the circulation, 

 and that they exert their influence by virtue of their peculiar properties. 



Conia digitaline and nicotine destroy the action of the heart; strych- 

 nia acts upon the spinal marrow ; opium, the woorara, and "poison of 

 serpents on the brain. 



Now, although the absorption of poisons, and their presence physi- 

 cally in the blood and organs, is a most important fact, — one, indeed, 

 u'pon which the whole science of toxicology reposes, — it is not to be im- 

 agined for a moment that it affords the slightest explanation of their 

 mode of action. 



The question still remains, whether they act by being applied to the 

 sentient extremities of the nerves, or in some other manner not yet 

 understood. 



Liebig has offered the explanation, that the poison by some chemical 

 change is converted into the substance of brain, which is thereby ren- 

 dered unfit to support vital energy. 



This hypothesis is entirely gratuitous, improbable, and, in view of 

 the rapid action of many substances on the brain, impossible. 



Fontana was much nearer the truth when about a century ago he 

 attributed death from the poison of the viper to the effect produced on 

 the blood. He was of the opinion that, injected into the veins of ani- 

 mals, it caused coagulation of the blood, which arrested the circulation. 

 He made more than six thousand experiments with vipers, repeated 

 and varied in every possible way. In regard to the coagulation of the 

 blood in this case, 1 am not able to d^ny that it may occur, as I have 

 not experimented with vipers ; but I am sure it is the reverse of what 

 takes place from the bite of the rattlesnake, for it is uniformly found 

 dissolved after death from this cause, and incapable of coagulating to 

 the same extent as in health. I am also certain that a change does 

 occur in the form of the globules of blood in pigeons and frogs poisoned 

 by woorara and the bite of the rattlesnake. 



If the wing of a bat or the web of a frog's foot be subjected during 

 life to observation beneath the focus of a microscope, innumerable small 

 bodies are seen hurrying along the arteries, towards their extremities, 

 traversing the small, hair-like vessels called capillaries, and returning 

 towards the heart by the veins. 



These bodies are the blood globules. They vary in form in dif- 

 ferent classes of animals, being circular and flattened in men, and ovoid 

 in birds and frogs. 



The integrity of these globules is essential to life ; for whenever they 

 become altered, they adhere to the sides of the vessels and to one 

 another, and can no longer traverse the capillaries. 



The theory that poisons alter the form of the globules, so as to render 

 Mis. Doc. 24 9 



