OF THE VENOM OF THE RATTLESNAKE. 45 



coagulum and the supernatant fluid were thrown into the tissues of full-grown 

 pigeons. Of six thus treated, all died with the usual symptoms. 



In a second series of experiments, to which I have already alluded (see chemistry 

 of the venom), the coagulum and supernatant fluid were separated by filtration; 

 the coagulum washed, and the two products injected separately into two pigeons. 

 In eight experiments of this kind it was found that the coagulum by heat was 

 always innocent, the fluid as uniformly poisonous. It is unnecessary to relate 

 these cases in detail, but it was further observed that the fatal cases died with the 

 usual rapidity, a fact which permits us to suspect that the venom loses no power 

 by being heated, and that the albuminoid compound, which constituted the coagu- 

 lum, was not poisonous before its condition was altered by elevation of temperature. 



We -thus arrive at the conclusion that the venom of the Crotalus is toxically 

 unaltered by freezing or boiling, and of course by the intermediate temperatures 

 to which it may be subjected. 



It is not a little curious that the animals which perished from the injection of 

 boiled venom exhibited very trifling local evidences of the action of the poison. I 

 am unable to offer any plausible explanation of this curious deficiency. 



Influence of Certain Chemical Agents on tlie Activity of Venom. — In the following 

 observations upon the influence of chemical agents on the activity of the Crotalus 

 poison, certain necessary precautions were carefully attended to, without which 

 the results attained would have been of but trifling value. Thus, for example, 

 in using strong acids, alkalies, etc., it was necessary to make sure that the caustic 

 action of these substances did not prove fatal to animals as small as the reed-bird. 

 This end was obtained by carefully neutralizing the substances employed, after 

 they had been allowed to affect the venom for a time. Where this could not be 

 done, as with alcohol, etc., the result was checked or tested by experimenting with 

 the substance alone, free from the presence of the venom. 



It will be sufficient to give detailed accounts of some of these experiments, and 

 to state merely the results of the remainder; since the precautions employed were 

 similar in all the cases. 



Alcohol. — I cannot find that Fontana actually mixed this fluid with venom, and 

 then essayed its powers, with the object of ascertaining to what extent they were 

 modified. Dr. Brainard^ was probably the first to make this direct observation, 

 not only with alcohol, but also with oil of turpentine, and the solutions of nitrate 

 of silver, ammonia, soda, and potassa. He found that the mixture of these agents 

 with venom did not alter or delay its action, provided the reagents were not of 

 caustic strength. 



Experiment. — The venom to be used having been previously tested and found to 

 be potent, two drops of it were treated with twenty-five drops of alcohol. A dense 

 coagulum formed, and at the close of ten minutes the mixture was injected into 

 the breast tissues of a pigeon, which died, with slight local signs of poisoning, at 

 the close of thirty-seven minutes. A check experiment was made at the same 

 time, to learn how much the amount of alcohol used (twenty-five drops) would 



' Smithsonian Report, 1854, p. 133. 



