PHYSIOLOGICAL ACTION OF VENOM OF BLACK SNAKE. 151 
the venoms of this class of snakes. Such early convulsions must 
not be confused with those due to failure of the respiration, which 
immediately precede death from cobra poisoning. 
With subcutaneous injection, the venom does not, as a rule, 
reach the blood with sufficient rapidity to occasion any extensive 
thrombosis, but under these circumstances the blood is found to 
have its coagulability greatly diminished or lost. These opposite 
conditions are in reality two phases of the same operation. 
As thrombosis in different regions of the circulation produces a 
great variety of sudden and surprising effects, which are generally 
absent after subcutaneous injection of the poison, the comparison 
of results obtained by the two methods of introduction of venom 
must be made with a due amount of caution. 
III.—Actioy or VENom on THE Bioop aNp Boop VESSELS. 
Through whatever channel the poison may be absorbed it sooner : 
or later reaches the blood stream, and is distributed thereby 
through all the tissues and organs of the body. Accordingly it is 
necessary to ascertain in the first place what changes it may 
occasion in the blood itself. Without such knowledge it-would 
be impossible to differentiate those effects produced on the various 
organs of the body which are to be attributed to the primary 
Sf Spération of the poison from those which are secondary to its 
Interference with the normal constitution of the blood. 
When the literature of this part of the subject is examined, one 
Notices the entirely different results obtained by observers experi- 
eating with various kinds of snake poison. Cobra poison would 
‘Appear to exert little effect upon the blood, but that it does have 
<n action is evidenced by the fluidity of the latter in the human 
mbiect, after death from cobra-bite. Occasionally too, the mucous 
‘ischarges from the body are stained with blood. These blood 
‘Changes are however relatively unimportant, and if an animal 
— the nervous symptoms it at once passes into a condition 
of complete health, With the poison of the viperidw, and to a 
tess extent with that of most colubrines, other than cobras, the 
