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 two careful investigators found definite signs of chromatolysis at 
varying stages to be constantly present in the central nervous system of the 
monkeys injected with these four colubrine venoms — namely, Cobra, Bun- 
garus fasciatus, Bungarus ceruleus, 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 go 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 1 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 résumé 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 cells 
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 
