PHYSIOLOGICAL ACTION OF VENOM OF BLACK SNAKE. 257 
metric charts, taken from animals injected with this venom. The 
first change he noticed in an animal after the introduction of 
cobra poison, was a decided quickening and deepening of the 
respiratory movement. This increase was no longer to be seen 
after the section of the vagi. The quickening was only temporary, 
and after an interval of uncertain duration, the respiratory move- 
ment, became slower, and less in extent. This diminution con- 
tinued until the blood was no longer: oxy ted, when the animal 
° 
died with the usual symptoms characteristic of asphyxiation. 
When a large dose (1 cc. of fresh venom), was introduced directly 
into the circulation of a dog, Wall found that thirty seconds after 
the injection, the animal was suddenly seized with asphyxial con- 
vulsions, in which it died in about one hundred seconds. Wall 
attributed these convulsions to a stimulation of the respiratory 
centre prior to extinction of the function of the same. This may 
be the correct explanation of the phenomena, but the injection 
of Pseudechis venom directly into the circulation produces pre- 
cisely the same series of events, and the explanation in this case 
is that the whole vascular system is quite suddenly thrombosed. 
The gradual extinction of all respiratory movement is, accord- 
to Wall, due to paralysis of the respiratory centre. Brunton and 
Fayrer! ascribe it partly to this cause, and partly to a curare-like 
action of the poison on the terminations of the phrenics in the 
diaphragm, whereas Ragotzi is of opinion that it is due to the 
latter alone, 
Wall’ has also investigated the action on the respiration, of 
the poison of the viper Daboia russellit. Its action in producing 
convulsions has already been discussed. If only small doses are 
subcutaneously injected, or if the venom be previously boiled, the 
respiration, after a preliminary acceleration, becomes slower and 
slower, until death occurs, 
Mitchell and Reichert? found that the venoms of Crotalus and 
Ancistrodon caused a primary increase in the number and extent 
1 Loe. cit. 2 Loe, cit. 3 Loc. cit. 
Q—July 3, 1995, 
