OF THE VENOM OF THE RATTLESNAKE. 43 



view, wc learn that in Crotalus its secretion is constantly acid, and in the Viper 

 neutral, while the saliva of the parotid in all animals yet examined is as unchange- 

 ably alkaline. Again, while saliva is a secretion of rapid formation, and appro- 

 priated to specific mechanical and chemical purposes within the economy, the 

 venom fluid is slowly elaborated, slowly reproduced when lost, and destined to no 

 end within the body which produces it. Lastly, its singular nature as a ferment, 

 poisonous to other animals as well as to its owner, constitutes a distinction, which, 

 with the other points of difference already considered, forbid the physiologist to 

 regard it as, in any true sense, a salivary secretion, or its forming organ as a sali- 

 vary gland. 



Effect of Various Temperatures on the Activity of Venom. — When I contemplated a 

 series of researches upon the antidotes to Crotalus poisoning, I planned and executed 

 a large number of experiments directed towards increasing our knowledge of the 

 influence of physical and chemical agents upon the noxious properties of venom. 

 Some of these researches were modified repetitions of work already done by others, 

 but the majority were novel, and appear to me to cast considerable light upon the 

 subject. 



Especially do they clear the ground for more just conceptions of the real value 

 and therapeutic possibilities of antidotes. Without them, also, no fitting idea of 

 the singular energy of this poison could be formed, nor should we be able to con- 

 ceive of the tenacity with which its powers are preserved in the presence of violent 

 chemical reagents and extremes of heat and cold. 



I was well aware that the dried venom retained its potency after two years of 

 climatic changes, and that even the fresh poison, although prone to partial decom- 

 position, might also remain active, after a sojourn of several weeks in an atmo- 

 sphere of 65° to 70° F. 



In the experiments upon the influence of rextreme temperatures, I was obliged 

 to resort to the following means : — 



First. I established the fact that dilution did not injure the venom; and next, 

 that minute quantities, as one-eighth or one-half of a di'op, were fatal to the reed- 

 bird within a few hours, more or less. As it was impossible to use large amounts 

 of venom, owing to the economy with which I was forced to employ it, I arranged 

 a tube of such size, that a marked half inch held one drop of a mixture made by 

 adding four drops of water to one of the venom. 



Experiment. — The marked tube was drawn to a capillary point, and a little venom 

 sucked up into it, and so manipulated as to leave in the tube one drop of the mix- 

 ture, representing one-fifth of a drop of venom. By very gentle suction, this was 

 next drawn two inches up the tube, and the capillary point below, closed in the 

 blowpipe flame. 



Thus prepared, the tube was plunged in a freezing mixture, and kept at a tempera- 

 ture 3° to 4° above zero F. At the close of half an hour, the tube was placed in 

 water at 70° F., and when the contents became fluid, the point of the tube was 

 broken off, and the venom ejected into the breast tissues of a reed-bird, which died 

 convulsed in twenty-seven minutes. Two repetitions of this experiment gave no 

 different result. 



