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 haemoglobin. 

 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 

 haemoglobin present may have been the cause of the effects noted; as a 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 i c.c. of rabbit serum 

 o.ooi gm. of crotalus venom, and to i 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 i 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): i c.c. dog serum and varying amounts of copperhead venom.] 



