256 VENOMS 
of a very neat and simple method, and with a sufficient degree of 
accuracy for practical purposes, the antitoxic power of an anti- 
venomous serum by measuring its antihæmolytic power.’ 
To this end it is sufficient to cause variable doses of serum to 
act on a given quantity of defibrinated horse- or rat-blood, to which 
a constant dose of venom is then added. We employ, for example, 
a 5 per cent. dilution of defibrinated horse-blood, which is portioned 
out in doses of 1 c.c. into a series of test-tubes. To each of these 
tubes in succession is added a progressively increasing quantity of 
the serum for titration, starting with 0-01 c.c., and continuing with 
0:02 c.c., 0°08 c.c., &c., up to O'lc.c. A control tube receives no serum. 
There are then introduced into all the tubes 1 decimilligramme of 
venom and 0 c.c. of normal horse-serum, deprived of alexin by 
previous heating for half an hour at 58°C. At a temperature of 
about 16° C. hemolysis commences to manifest itself in the control 
tube in from fifteen to twenty minutes. It takes place in the other 
tubes with a retardation which varies with the dose of serum 
added. Tubes are to be noticed in which it does not occur even 
after the lapse of a couple of hours. 
Experience shows that we may consider as good for therapeutic 
use serums which, in a dose of 0°05 c.c., completely prevent hæmo- 
lysis by 1 decimiligramme of COLUBRINE venom, such as that of 
Cobra, Krait, &c., and those that in a dose of 0°7 c.c., prevent 
hemolysis by 1 milligramme of the venom of Lachesis or Vipera 
berus. 
By a method calculated upon the foregoing, it is likewise 
possible to measure the antihemorrhagic activity of an anti- 
venomous serum, for the parallelism existing between the anti- 
neurotoxic and antihamolytic actions of serums occurs again, as 
I have been able to establish in conjunction with Noc, between 
the antihæmorrhagic and antiproteolytic action of the same serums. 
' Calmette, Comptes rendus de l'Académie des Sciences, 1902, No. 24; Preston 
Kyes, Berliner klinische Wochenschrift, 1904, No. 19. 
