154 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



venoms of four different colubrine snakes and one viperine snake had been 

 carefully studied previously. They experimented chiefly on monkeys, usually 

 giving the venom subcutaneously, in order to obtain a longer action of the 

 poison on the nervous system in general. 



These tv^o careful investigators found definite signs of chromatolysis at 

 varying stages to be constantly present in the central nervous system of the 

 monkeys injected v^ith these four colubrine venoms — namely, Cobra, Bun- 

 garus fasciatus, Bungarus cceruleus, and Enhydrina valakadien, but not in the 

 case of daboia- venom toxication. In the case of the venom of Naja tripudians 

 definite histological lesions are demonstrable only when the animal lives 

 longer than two or three hours after the injection of the venom. On the 

 other hand, the venom of Enhydrina may produce within 90 minutes just 

 as pronounced chromatolytic degeneration as in the cases where death does 

 not result until several hours after the injection. The effects of the venom 

 of Bungarus fasciatus are still somewhat different, inasmuch as an incub- 

 ation period of many hours is required before nervous symptoms appear. 

 Where the symptoms appear within several hours, the animal usually dies 

 within I to 3 days, but should the symptoms appear in 2 to 6 days, the 

 animal dies in a week or longer with the nervous and muscular atrophic 

 symptoms. Lamb calls the first group the acute and the last the chronic 

 poisoning. Cobra venom is never known to produce the latter form of 

 toxication, and therefore it agrees with the acute form of poisoning of 

 bungarus venom. 



The intensity and extent of histological lesions observed in all cases of 

 poisoning by these colubrine venoms appear to depend on the period inter- 

 vening between the time of the injection of venom and the time of death. 

 With the same venom, the longer the interval the more marked are the chro- 

 matolytic lesions. In comparing one venom with another the lesions are more 

 pronounced with the kind which kills the animal after a longer duration of 

 toxication. Besides, a certain qualitative difference in activity seems to 

 modify the result, viz, the venom of Enhydrina is not only rapid in 

 action, but also displays a wider affinity for nerve tissues other than the 

 central ganglia. 



From their vast materials Lamb and Hunter give a resum^ in which all 

 observed lesions are so represented as to enable one to comprehend the 

 processes of chromatolysis and the sphere through which the ganglion ceUs 

 have to pass under the influence of the neurotropic toxins of snake venom. 

 In the first place, there is a deep and rather diffuse staining of the ganglion 

 cells. In this diffusely stained plasma the Nissl granules are to be seen 

 as deeper-stained bodies, still quite consistent, with rather ill-defined edges. 

 The Nissl bodies next seem to begin to dissolve in the cell plasma, and they 

 suggest the appearance of pieces of metal being acted upon in a strong acid 

 medium. This leads to the next stage, which is still that of diffusely stained 

 cells, but with smaller granules in the plasma. Then the granules and the 



