EXPERIMENTAL VENOM POISONING IN ANIMALS 119 



Wall divides the experimental cases of toxication with this venom into two 

 classes, acute and chronic. In the acute cases death takes place within 48 

 to 72 hours after the injection of the venom. There is sometimes a slight 

 swelling at the point of injection. Profuse salivation and vomiting are usual 

 symptoms. Muscular twitching is often observed. The paralysis of respira- 

 tion is the cause in these cases. There is no extravasation around the site of 

 inoculation and the degree of local swelling is distinctly much milder than in 

 cases of cobra poisoning. The effusion of pinkish fluid is seen in the areolar 

 tissue at the inoculation spot, indicating the destruction of some of the red 

 blood corpuscles. The blood withdrawn from the heart or venae cavae of 

 the poisoned animals after death clots firmly on exposure to the air. Wall 

 calls attention to the remarkable difference in the action of the venom of 

 Bungarus fasciatus and that of Naja tripudians in the fact that, with the 

 latter venom, if the animal survives 49 hours after the injection it ultimately 

 recovers. In contrast to this the venom of Bungarus fasciatus, if used in such 

 amounts as not to produce death within 2 to 3 days, brings about a series 

 of symptoms quite different from those described in the acute cases. In 

 these chronic cases the symptoms begin to manifest themselves in from 2 to 

 12 days, and before that period no symptoms * are seen. After this interval 

 of time a diseased condition, more or less active, begins, which, Wall states, 

 invariably ends in death. The main symptoms are the loss of appetite, great 

 depression, and marked diminution in the urinary secretion. Great muscular 

 weakness 2 is evident, with slight failure of the respiratory functions and an 

 irregular rise of temperature. Purulent discharges from the eyes, nose, and 

 rectum are also observed. There is no tendency to haemorrhages. Death 

 ensues after a few days' illness. In these chronic cases the coagulability of 

 the blood is found to be impaired. 



Lamb found that if a very large amount of the bungarus venom is intro- 

 duced directly into the circulation of the blood of rabbits death occurs in a 

 few minutes, and post-mortem examination reveals the presence of extensive 

 intravascular thrombosis. 



PSEUDECHIS. 3 



The effects of the venom of Pseudechis porphyriacus, the Australian black 

 snake, are exerted principally on the three most vulnerable points in higher 

 organisms: the blood, the heart, and the respiratory center in the medulla 

 oblongata. Death can result from the alteration produced in any one of 

 these three, and this depends on the concentration with which the venom 

 reaches the circulation. When this concentration attains a certain limit, 

 death may be almost instantaneous, from coagulation of the blood in the 

 vessels terminating the circulation. This happens when small animals are 

 bitten, or when the poison is introduced in adequate quantity directly into 



1 Lamb mentions depression and a progressive loss of weight in this period. He used rabbits, rats, and 



monkeys. 



* Lamb inclines to think that paralysis accompanies this muscular atrophy. 

 8 C. J. Martin. On the physiological action of the venom of the Australian black snake (Pseudechis 



Porphyriacus). 1895. Read before the Royal Society of New South Wales. 



