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PHYSIOLOGICAL ACTION OF VENOM OF BLACK SNAKE. 211 
In a previous section I have mentioned a similar occurrence in 
many of my experiments with the intravenous injection of 
Pseudechis venom. At first this maintenance of a considerable 
pressure in the arteries after the sudden death of the animal 
puzzled me greatly. There could be however only one explanation 
of the phenomenon, viz.: that the blood cowld not empty itself as 
usual into the veins. In my experiments the reason was that the 
arterial system was blocked by the occurrence of intravascular 
clotting, and it is quite possible that this was also the explanation 
in Brunton and Fayrer’s experiments. 
In the experiments made by these observers death usually 
occurred from asphyxia, during which the blood pressure curve 
exhibited the same rise of pressure above the normal as obtains 
when an unpoisoned animal is asphyxiated. 
Speaking of this maintenance of circulatory efficiency, Brunton 
and Fayrer say,—‘ The long continuance of the cardiac pulsations 
after apparent death excludes failure of the circulation as the 
usual cause of death ; and we are thus brought, by exclusion, to 
regard death caused by the bite of the cobra, or by its poison 
introduced into the body in any other way, as death from asphyxi1. 
The truth of this view is well illustrated by a series of experiments 
which show that the vitality of the heart may be retained for a 
considerable time if the respiration is kept up. It shows also 
that the convulsions which have been remarked by Russell and 
all subsequent observers as almost always preceding death are not 
due so much to the action of the poison itself on the nervous 
centres, as that they depend on the irritation which is produced 
in them by the venosity of the blood.” 
(0)—The effect of Pseudechis venom upon the excised heart of cold- 
blooded Vertebrates. 
Thave experimented with the excised hearts of frogs and turtles. 
In the case of either of these animals a perfusion cannula was 
mserted in the ventricle and tied. The cannula was connected 
with a Ludwig and Coat’s apparatus, and the record of the heart- 
