244 C. J. MARTIN. 
intravenously, or large quantities subcutaneously, are injected, 
the more obvious effect is that produced upon the heart, butif 
the delivery of the venom be slower, as when it is subcutaneously 
injected, in not too large amount, the function of respiration is the 
one more particularly interfered with, whilst the circulation may be 
well maintained. In fact, were two separate observers to experi- 
ment, the one with intravenous, the other with subcutaneous 
injections, the conclusion of the former would be that the principal 
action of the venom was that of a cardiac poison, while the latter 
might consider -that any interference with the circulation was 
altogether subsidiary to the action of the poison on the respiratory 
mechanism. 
Different species of animals also exhibit some variation in the 
relative degree of sensitiveness of their vascular and respiratory 
mechanisms to the poison. In dogs the effect on the vascular 
mechanism is, under similar conditions, generally more manifest 
than in rabbits, whereas the latter appear to be particularly 
sensitive to the influence of the poison in that portion of the 
nervous system connected with respiration. It must, however, be 
distinctly understood, that in all animals the venom produces @ 
profound paralysing effect upon the heart, and even in rabbits, 
life can be prolonged but a few minutes by means of artificial 3 
respiration. In those experiments in which immediately @Y 
signs of diminished respiratory activity were obvious, artificial 
inflation with warmed air was resorted to, the blood pressure fell 
to within a few mm. of zero, and the animal died very shortly . 
after extinction of ordinary breathing had occurred. 
It would appear as if the poison must reach a certain proportion ‘ 
in the circulating blood, before it can seriously interfere bigs 
cardiac contractions, but once this proportion is reached, the heat’ ; 
is very speedily and profoundly affected. When the meee 
of the venom is slow, it may however effect a gradual paralysis re 
the more sensitive respiratory nervous mechanism, before aS 
present in the blood in sufficient concentration to produce ~ 
appreciable diminution in cardiac activity. 
