202 VENOMS 
The resistance of the hæmolysins 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 antihæmolysing, and capable of perfectly protecting the 
red corpuscles in vitro and wn vivo. 
I have been able to prove that the antineurotoxic property of 
antitoxic serums with regard to the venoms of COLUBRIDÆ is 
pretty much on a par with their antihæmolysing property, so that 
it is possible to measure in vitro the antitoxic activity of a serum 
by establishing the degree of its antihemolysing activity. Thus 
we see that a serum, which is antitoxic and antihemolytic with 
respect to the venom of Naja, is likewise antihæmolytic as 
regards the other COLUBRINE-venoms, and even certain venoms 
of VIPERIDÆ. 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 Cobra-venom precipitates the latter in more 
or less concentrated solution. Jt 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-venom ; the formation of precipitate 
is therefore entirely independent of that of antitoxins (G. Lamb).! 
(3) Agglutinins of Venoms.—Besides their hemolytic action, 
it is easy to observe that certain venoms, especially those of 
VIPERID&, agglutinate the red corpuscles, and that the substance 
that produces this agglutination is different from the hemolysing 
substance; for ft acts rapidly at a temperature of 0° C., at which 
hemolysin 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. 
