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Effects of Snake Venoms on Snakes

1946; American Society of Ichthyologists and Herpetologists; Volume: 1946; Issue: 4 Linguagem: Inglês

10.2307/1438111

1938-5110

Paul L. Swanson,

Erythrocyte Function and Pathophysiology

IN 1931 I started a series of experiments on snake venoms in order to procure comparative data on the effects of venoms on various species of snakes. The war brought the work to a standstill in 1941, after I had concluded 58 experiments. Although the small number of experiments does not permit definite conclusions to be drawn, the work is now summarized due to the improbability of its being continued to any extent in the near future. The experiments were performed in widely scattered places wherever snakes were available; freshly extracted liquid venom was always used. It was collected in a rubber covered glass graduate, measured, and injected with a hypodermic syringe. All instruments were sterilized by boiling before use, and control experiments were made by injecting sterile distilled water in the same manner as venom in the regular experiments. The specimens injected were under observation for at least a week afterward; when death ensued, autopsies were usually made, and the internal organs macroscopically inspected. These post-mortem examinations were not more thorough than was necessary to ascertain definitely that death was toxic rather than traumatic. Since the exact amount of toxic constituents in liquid venom can not be determined accurately, quantitative comparisons are only approximate. However the use of such venom simulates more naturally actual snake bites. Air temperatures, time of day, source of snake injected, source of snake from which venom was extracted, time of various symptoms, and the results of the autopsies were recorded. These data are abstracted below. The choice of snakes used in the experiments was based more on expediency than desirability. In some experiments the venom from as many as 7 snakes was used in one injection. In connection with this series of experiments, I made 134 venom extractions. Venom yields ranged from none at all up to 21 minims (1.26 cc) from a Crotalus atrox. Twenty extractions from Sistrurus catenatus catenatus yielded from .25 to 2 minims each, averaging about 1.2 minims (0.07 cc); 37 extractions from C. horridus horridus varied from 0 to 6 minims, averaging about 2.8 (0.18 cc); 46 extractions from Agkistrodon mokeson mokeson showed a variation from .50 minim. to 4.5 minims, averaging about 2.5 minims (0.15 cc). Extractions were also made from Agkistrodon piscivorus, A. mokeson laticinctus, and Crotalus atrox, but the specimens used were too few, too small or were used without a proper rest period, to supply any pertinent figures. My results do not show any great divergence from other published figures on venom yields from these species. Whenever the same snakes were used for several extractions, subsequent extractions were never made within a period of less than two weeks. I am grateful to Clinton Coulter, M.D., for assisting me in initiating the work, and for establishing a method of procedure in injecting and autopsying, and to Arnold J. Schauman, David C. Swanson, and Mrs. Eva Henderson, who aided me from time to time.