216 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
moribund state —showed great loss of bactericidal properties. The three 
kinds of bacteria multiplied in this serum very freely, while all were com- 
pletely destroyed except (in a few experiments) B. coli, which showed con- 
siderable diminution until after 6 hours, when increase began. In another 
series, 0.03 gm. of crotalus venom was injected into the blood of animals, 
taken after 45 minutes; full serum was used for inoculation of bacteria; 
practically the same result as in the previous series was obtained. 
(2) Blood mixed with venom in vitro: In this series rabbits only were 
employed. The venom solutions were placed in Nuttall bulbs and the blood 
from the femoral artery was permitted to stream into them. In each experi- 
ment 0.006 gm. of venom were mixed with 20 to 30 c.c. of the blood. Coagu- 
lation was very slow or completely inhibited, and the serum was obtained 
when necessary by centrifugalization. It invariably contained hemoglobin. 
The results all show that the bactericidal power of the venomized blood 
is completely abolished. This series of experiments may be open to the 
criticism that the increased nutritive value of the serum because of the 
hemoglobin present may have been the cause of the effects noted; asa control, 
therefore, peptone was added to the serum in the proportion of 0.006 gm. of 
peptone to 20 c.c. of serum. From this experiment it follows that improve- 
ment in nutritive value reduced bactericidal effect, but in far less amount 
than is noted in the parallel case of venom. That the nutritive change is 
unimportant is shown by the first series of experiments, in which the poison- 
ing was done in vivo, and also by the following experiments in which venom 
was added directly to the separated serum. 
(3) Direct addition of venom to the serum in vitro: In this series serums 
of normal rabbits and dogs were employed. To 1 c.c. of rabbit serum 
0.001 gm. of crotalus venom, and to 1 c.c. of dog serum 0.006 gm. copper- 
head venom were added. The results were the abolition of the germicidal 
powers of these serums. In order to determine the least quantity of venom 
required to remove the bactericidal properties of the serum varying quan- 
tities of copperhead venom were employed. Dog serum was chosen with 
B. typhosus. In each case 1 c.c. of serum was used. Table 18 gives one 
of these experiments, and the number of bacteria grown on one plate is shown. 
TABLE 18. 
[Experiment XXXII (a): 1 c.c. dog serum and varying amounts of copperhead venom.] 

Amount of copperhead venom employed. 
Time of contact 
before plating out. 
0.0005 gm 0.0002 gm 0.0001 gm. 0.00005 gm 0.00002 gm. 
Immediately. .] 5,970 3,070 4,290 4,940 3350 
r hourse<! o: 6,240 3,960 1,830 2,620 920 
3) hours).:<-..- 12,810 10,000 6,730 1,350 593 
Oehourse sco: Innumerable 100,000 13,140 7 
24 NOUFS), fcc bs ate ceieerene Innumerable | Innumerable 10,000 ° 

