EFFECTS OF VAEIOUS PHYSICAL AND CHEMICAL AGENTS 95 



there is still some heat-incoagulable principle left in the heated venom which 

 may cause death when used in a sufficient quantity.^ 



According to Calmette the venoms of Lachesis are the most sensitive to heat 

 and partly lose their toxicity even at 65° C. Wolfenden mentions that cobra 

 venom coagulates at 70° to 80° C. and daboia venom at 65° to 73° C. 



It may be remarked that the proteins of venoms when once coagulated by 

 heat are entirely non-poisonous, as these can first be freed from the non- 

 coagulable constituents by washing and be injected into animals witliout 

 producing any symptoms. 



From these facts it becomes evident that most of the active principles of 

 the Colubridce reside in the non-coagulable portion of the venom, while the 

 greater part of the poisonous properties of the Viperidae venoms are inherent 

 to the coagulable proteins, and this is also confirmed by various evidence. 



Effect of dry heat : A prolonged heating of dried venom in a hot-air 

 chamber at 130° C. does not destroy the activity of the venom. 



Dialysis: The venoms of Viperidae, which mostly contain coagulable 

 proteins as toxic constituents, do not difi'use through dialyzer — either vege- 

 table or animal membrane, while those of the Colubridse slowly dialyze through 

 the first, but much more tediously through the latter membrane. It is on 

 account of this property that Weir Mitchell and Reichert classified this non- 

 coagulable, dialyzable principle with "peptone," although it possesses some 

 other quahties as a peptone. 



The effect of filtration : The venoms of Colubridas do not lose their toxicity 

 in any noticeable degree by passing through an ordinary or Martin's gelati- 

 nized Chamberland bougie. On the other hand, the venoms of Viperidae 

 leave all their active principles on the gelatinized bougie, the filtrate in this 

 case being almost or entirely inactive. Madsen and Noguchi found a 50 

 per cent loss of toxicity in crotalus venom after passing through a usual 

 Chamberland bougie. C. J. Martin^ filtered the venom of Pseudechis through 

 the gelatinized bougie under the pressure of 50 atmospheres, and found that 

 the hgemorrhagic principle, similar to the active, coagulable proteins of all 

 viperine or crotaline snakes, remains behind the filter, while the diffusible, 

 non-coagulable protein — albumose — passed into the filtrate. The latter is 

 found to attack the respiratory center. Filtration through animal (but not 

 wood) charcoal retains all of the poisonous matters and the filtrate is 

 innocuous. (Mitchell and Reichert.) 



The effect of cold : Lumiere and Nicolas ^ tested the effect of cold produced 

 by evaporating hquid air. The cobra venom employed by them was a 

 I per cent dilution. A portion of it was subjected to the action of liquid 

 air for 24 hours, and another for 9 days at a temperature of —191° C. Its 

 toxicity remained unaltered after the treatment. 



1 The venoms of Crotalus adamanteus and Ancistrodon piscivorus are both still active after a brief 



boiling. Mitchell and Reichert, loc. cit. 



2 C. J. Martin. Notes on method of separating colloids from crystalloids by filtration. An explana- 



tion of the marked difference in the effects produced by subcutaneous and intravenous injection 

 of the venom of Australian snakes. Roy. Soc. of N. S. Wales, August 5, 1895. 



3 Lumifere, Aug., and Joseph Nicolas. Province medicale, Sept. 21, 1901. 



