358 THE SNAKES OF SOUTH AFRICA. 
in varying proportions, hence the reason of the differences in 
the effects on the human body and the symptoms arising from 
those effects. 
The nerve poison (neurotoxin) can be separated from the 
blood poison (hemorrhagin) of Cobra venom, by adding lecithin 
dissolved in chloroform, with a solution of venom, and shaking 
vigorously. The blood-poison combines with the lecithin to 
form an active lecithide which dissolves in the chloroform and 
can be afterwards precipitated by ether. 
The neurotoxin or nerve-poisoning principle of the venom 
remains in the liquid solution. The part which has been precipi- 
tated, if injected into animals, destroys the red corpuscles of 
their blood, inducing hemorrhage into the tissues. Its action is 
very rapid, especially when a concentrated solution is used, being 
then much more active than before separation from the neuro- 
toxin. 
Weight for weight, the venoms of the different species of 
snakes vary considerably. The venoms of the Mamba, Cape 
Cobra, and Boomslang have as powerful poisoning effect as 
three times the weight or bulk of Puff Adder, Berg Adder, or 
Night Adder venom. 
The poisonous effects of all venoms vary according to the 
size and vital resistance of the victim. For instance, a cat is of 
about the same weight, or even less, than a large fowl or rabbit, 
yet its power of resistance to the poisonous action of venom is 
considerably greater. A Boomslang was forced to bite the 
bared thigh of a domestic cat of adult size, and was permitted to 
retain its grip for half a minute. The cat gradually developed 
symptoms of poisoning and died in thirty hours. Large cock 
fowls and rabbits bitten by the same snake died within fifteen 
minutes. An interesting feature of these cases was the different 
symptoms. The cat was strongly acted upon by the blood- 
poisoning principle of the venom, for the wound oozed blood 
all the time, and the mucous surfaces discharged blood ; and after 
death, extravasated blood was found in various tissues. On 
the contrary, no such symptoms were apparent in the fowls 
and rabbits. The neurotoxin or nerve-poisoning principle in 
the venom caused almost instant paralysis of the motor nerve 
centres. After death, little or no alteration to the blood could 
be detected. 
