EFFECTS OF VARIOUS 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 without 
producing any symptoms. 
From these facts it becomes evident that most of the active principles of 
the Colubride reside in the non-coagulable portion of the venom, while the 
greater part of the poisonous properties of the Viperide 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 Viperide, which mostly contain coagulable 
proteins as toxic constituents, do not diffuse through dialyzer — either vege- 
table or animal membrane, while those of the Colubridz 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 qualities as a peptone. 
The effect of filtration: The venoms of Colubridz 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 Viperide 
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 hemorrhagic 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: Lumitre and Nicolas? tested the effect of cold produced 
by evaporating liquid air. The cobra venom employed by them was a 
1 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. 

1The venoms of Crotalus adamanteus and Ancistrodon piscivorus are both still active after a brief 
boiling. Mitchell and Reichert, oc. cit. 
2C. 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 Lumiére, Aug., and Joseph Nicolas. Province médicale, Sept. 21, 1gor. 
