POISONOUS SNAKES OF NORTH AMERICA. 459 



objectiou that some of tlie fluid is lost, that it is unnecessarily brought 

 into contact with substances which may aflect its nature more or 

 less, and that it is not obtained in a concentrated state, as it must be 

 washed out with distilled water. Dr. Weir Mitchell, after having seized 

 the snake by the neck with the tongs or loop, forced a saucer between 

 the jaws, into which the enraged animal would then bite vigorously, 

 leaving a quantity of the poison on the saucer. Prof. Kaufman having 

 experienced that the snake often breaks its teeth on such a hard sub- 

 stance, or even refuses to bite, used a stick covered with rubber. The 

 late Dr. C. S. Allen, of New York, for the same reasons covered the 

 mouth of a wineglass or similar vessel with an animal membrane 

 through which he induced the snake to strike the hollow teeth, the 

 fluid being squirted into the glass. Dr. Paul B^rringer, of the Uni- 

 versity of Virginia, has, it seems to me, improved upon this method by 

 using several thicknesses of Altering paper, the object being to clean 

 the fangs of possibly adhering saliva, and thus prevent the venom from 

 coming in contact with foreign substances and the microbes inhabiting 

 them. 



The substance thus obtained is a more or less yellowish, exception- 

 ally colorless, transparent, sticky fluid, without any appreciable smell 

 or taste, easily soluble in water, insoluble in absolute alcohol or ether. 

 If vigorously shaken it becomes frothy. Examined under the micro- 

 scope, epithelial cells and other impurities are found, as well certain 

 albuminoid bodies resembling micro-organisms, but they do not respond 

 to the dye tests for bacteria, nor are they multiplied by cultures. 

 Drs. Mitchell and Keichert have demonstrated the i)reseiice of bacteria 

 (/. c. pp. 6-7), but their own researches, as well as those of others, 

 also show that they form no constant or essential accompaniment. 



Mitchell and Keichert (/. v. p. 137) injected large quantities of the 

 pure micrococci from a sixth generation, in various manners, into 

 rabbits, cats, i)igeons, etc., but no signs of any lesions resembling 

 those of venom i^oisoning were observed. 



Drs. Wolfenden and Dawson Williams* endeavored to grow cobra 

 venom in gelatine, " but without the slightest success;" Dr. A. Yiaud- 

 Grand-Maraist states that "bacteria and other protoorganisms are 

 seen to make their appearance when the solutions of the venom 

 commence to undergo alterations, but only then." 



Fredet is said to have made similar observations, and Kaufniann| 

 corroborates these statements from his own experiments. 



Another essential point is, that even boiling, unless continued for a 

 long time, does not altogether destroy the poisonous qualities of the 

 fluid. Mitchell found that the rattlesnake poison suflers a gradual 

 mipairment of the toxicity of the venom increasing with the increase 



*Journ. Physiol., Cambr., vii, 1886, p. 331. 



t Diet. Encycl. M<5dec., Paris (3 ser.), ix, 1881, p. 388. 



t Yen. Vip., 1889, p. i; Vip. France, 1893, p. 23. 



