128 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
inclined to suggest the reflex nature of salivation through irritation of the 
gastric branches of the vagus. Whatever the primary effects may be, the 
final result was always a diminution in the secretory function. 
In investigating the cause of respiratory failure in cobra poisoning, Brunton 
and Fayrer called attention to the remarkable fact that the end-plates of the 
phrenic nerves become completely insensible to the strongest stimuli, while 
the sciatics and vagus still retain a considerable amount of irritability. Thus, 
the ultimate arrest of respiration is probably due, in part, to paralysis of the 
medulla, and, in part, to paralysis of the motor-nerve endings in the respi- 
ratory muscles. 
In regard to the effects of cobra venom upon the enervation of the circu- 
latory system, Brunton and Fayrer consider this venom to have almost no 
direct paralytic effects. It is well known that the cause of death in cobra 
poisoning is usually respiratory failure, with the heart still beating vigorously. 
But when a concentrated solution of venom is directly introduced into the 
circulation of frogs the heart stops at once in systole. ‘The same is true when 
an excised heart of frog is immersed in a strong venom solution. The cessa- 
tion of the cardiac activity is not of a paralytic, but of a tetanic nature. This 
cessation of an isolated heart can not be due to the stimulation of the inhib- 
itory center contained within it; for atropin, which paralyzes inhibitory 
ganglia, does not restore the movements. It is probably not due to the par- 
alysis of motor ganglia, as the heart does not stop in diastole, but in systole, 
and resists distention by fluid within it. Brunton and Fayrer thought that 
the most probable cause was the stimulating effects of the venom upon the 
heart, resulting in the tetanic state of the latter. The inhibitory branches of 
the vagus are sometimes paralyzed. 
In this place it may be mentioned that the capillary circulation is not 
unaffected, but is greatly increased after the injection of the poison. Judging 
from the high blood pressure after the heart ceases to beat, the arterioles and 
capillaries must be much contracted. 
Wall reached the conclusion that the principal action of cobra venom on 
the nervous system consists of an extinction of functions, extending from 
below upwards, of various nerve centers constituting the cerebro-spinal 
system, and especially acting on the respiratory center and on those other 
ganglia allied to it in the medulla, which are in connection with the vagus, 
the spinal accessory, and hypoglossal nerves; and that it is directly to this 
destructive action that we have to attribute death in most cases of cobra 
poisoning. He observed an acceleration of the respiration rate, which does 
not occur when the vagus is cut before the injection of the venom. 
Ragotzi,! going over practically the same field covered by the work of Brunton 
and Fayrer, found that, if sufficient time elapses from the time of the injection 
to the manifestation of the action, cobra venom affects and paralyzes the 
intramuscular endings of the motor nerves. The paralysis of the nerve- 

1 Ragotzi. Ueber die Wirkung des Giftes der Naja tripudians. Virchow’s Archiv, 1890, CX XII, 2or. 
