202 VENOMS 



The resistance of the hsemolysins of venom to heat (which, 

 according to Morgenroth, may extend to heating for thirty minutes 

 at a temperature of 100° C.) explains how it is that the serum 

 of horses immunised by means of venoms heated to 72° C. is 

 distinctly antihsemolysing, and capable of perfectly protecting the 

 red corpuscles in vitro and in vivo. 



I have been able to prove that the antineurotoxic property of 

 antitoxic serums with regard to the venoms of Colubrid^ is 

 pretty much on a par with their antihsemolysing property, so that 

 it is possible to measure in vitro the antitoxic activity of a serum 

 by establishing the degree of its antihjEmolysing activity. Thus 

 we see that a serum, which is antitoxic and antihremolytic with 

 respect to the venom of Naja, is likewise antihtemolytic as 

 regards the other CoLUBRiNE-venoms, and even certain venoms 

 of ViPERiD^. Here we have a very important fact, for it enables 

 us to measure in vitro the activity of antivenomous serums. 



(2) Precipitins of Venoms. — The serum of rabbits treated with 

 increasing doses of Co6ra-venom precipitates the latter in more 

 or less concentrated solution. It has no effect as regards other 

 venoms. On the other hand, the serum of a strongly immunised 

 horse, the antivenomous power of which was pretty considerable, 

 gave no precipitate with Co&ra-venom ; the formation of precipitate 

 is therefore entirely independent of that of antitoxins (G. Lamb).' 



(3) Agglutinins of Venoms. — Besides their hsemolytic action, 

 it is easy to observe that certain venoms, especially those of 

 ViPERiDiE, agglutinate the red corpuscles, and that the substance 

 that produces this agglutination is different from the haemolysing 

 substance ; for it acts rapidly at a temperature of 0° C, at which 

 hsemolysin manifests its effects only with extreme slowness. 

 Heating to 75" C. destroys this agglutinant property (Flexner and 

 Noguchi). 



' Lancet, April 2, 1904, pp. 916-921. 



