THE PHYSIOLOGY OF POISO^^IXG 203 



substances (casein, albumins of ox-serum) in solution, has shown 

 that Cobra-Yenom and that of Vipera disintegrate the albuminoid 

 molecule ; but the latter remains soluble after the addition of 

 formol and is no longer precipitable by acetic acid. The hydro- 

 lysis never leads to the stage of peptone, but only to the forma- 

 tion of albumoses which give biuret-reaction. 



The action of venoms upon fibrin may be demonstrated in vitro 

 by bringing sufficient quantities of venom, 1 centigramme, for 

 example, into contact with small fragments of non-heated fibrin, 

 derived from blood clots from an ox, rabbit, or birds, and carefully 

 washed. These fragments soon separate from each other, and 

 become dissolved in a space of time which varies according to the 

 venom used. The ViPERiNE-venoms, especially those of Lachesis 

 and Ancistrodon, are the most active. Fijjer-venom is much less 

 so, and the venoms of CoLUBRiDyE are the slowest. 



This proteolytic action of the various venoms corresponds pretty 

 exactly to their coagulant and decoagulant action on rabbit- or 

 horse-plasma, so that, as I have already stated, we must suppose 

 that the property possessed by ViPERiNE-venoms of more or less 

 rapidly dissolving blood which they have caused to coagulate, 

 results from the fact that these venoms contain, in addition to a 

 coagulant substance, another substance which is strongly proteolytic. 



The latter is destroyed by heating. Lachesis-Yenom, when 

 heated to 70° C, no longer has any dissolving action on either 

 gelatine or fibrin. Moreover, antivenomous serum furnished by 

 horses vaccinated against heated venoms does not prevent proteo- 

 lysis by non-heated venoms. On the other hand, the serum of 

 animals vaccinated against ViPEEiNE-venoms, simply filtered by 

 the Chamberland process and non-heated, affords perfect protec- 

 tion to gelatine and fibrin against the dissolving action of these 

 venoms. 



