202 VENOMS 



The resistance of the hgemolysins of venom to heat (wliich, 

 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 ui 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 antihremolysing property, so that 

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

 by establishing the degree of its antihosmolysing activity. Thus 

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

 respect to the venom of Naja, is likew^ise antihasmolytic 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) PrecipitinH of Venonifi. — The serum of rabbits treated with 

 increasing doses of Cobra-yenom 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 Cobra-Yenom. ; the formation of precipitate 

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



(3) Agglutinins of Venoms. — Besides their hgemolytic 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 htemolysing 

 substance; for it acts rapidly at a ten]perature of 0" C, at which 

 haemolysin 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. 



