GENERAL PROPERTIES AND ACTIONS OF THE VENOM. 



77 



appears that in 3 hours the pigeon is able to eliminate or destroy a part, but 

 only a relatively small part, of the injected venom. 



The results of similar experiments with mice were not as regular as those 

 with the pigeons. 



Influence of administration of venom in fractional doses to mice. 



It has been noted before that the reaction of the individual mouse to 

 the heloderma venom varies quite markedly and that frequently mice will die 

 as a result of the injection of a dose which usually would prove to be sublethal. 

 It seems that such has been the case in these experiments. While 0.15 to 0.12 

 mg. of venom may be considered as the lethal dose for mice, we find that some 

 mice which received only 0.08 mg. of venom died as a result of the injection, 

 even though 3 hours intervened between the injection of the two parts. On 

 the other hand, some mice which in two or three injections received a quantity 

 of venom equal to the minimal lethal dose survived. In view of these latter 

 experiments, it appears probable that the injection of a minimal lethal dose in 

 fractional parts does not necessarily cause the death of the mouse; we must, 

 however, consider that 0.12 mg. is not necessarily a lethal dose. 



In the case of the pigeon, within a few hours a relatively very small part of 

 the venom is either eliminated or somehow transformed into such a condition 

 that it is no longer injurious to the sensitive parts of the central nervous sys- 

 tem of the injected animal. 



These results agree with the effect we observed in animals in which the 

 venom had been introduced by means of collodion capsules. Here also, owing 

 to the slow diffusion of the venom, the lethal effect was much delayed and in 

 some cases the animals, which would have died if the same amount had been 

 injected directly, recovered. 



SUSCEPTIBILITY OF VARIOUS SPECIES OF ANIMALS TO 

 HELODERMA VENOM. 



We have tested the susceptibility of warm-blooded vertebrates, cold- 

 blooded vertebrates, and invertebrates to the venom of the Heloderma. In 

 comparing the resistance of the warm-blooded vertebrates to heloderma venom 

 we have used as a standard for comparison the minimal lethal dose per kilo- 

 gram of body-weight.* 



*We have not compared the differences in functional disturbances, as these seemed to bear but little relation- 

 ship to the minimal lethal dose. In certain cases the animals were severely affected by the injection of venom, but 

 were relatively resistant to its lethal effect. 



