348 THE SNAKES OF SOUTH AFRICA. 
Three drops of Puff Adder venom is enough to cause such 
extensive hemorrhage into the tissues of a man as to kill 
him. 
In a man whose blood is altered by habitual indulgence in 
alcohol even in moderation, less than a drop would suffice to 
kill him. In monkeys which have been given a fair quantity of 
alcohol daily for a month, about a quarter of a drop of Puff 
Adder venom is sufficient to kill them. They die of hemorrhage 
and mortification. Often the site of the injection turns black. 
This mortification of the tissues at the site of the entry of the 
venom, spreads into the body and causes death. 
DISCHARGING VENOM. 
It is believed by most naturalists that the act of gaping the 
jaws and erecting the fangs causes an automatic action of the 
muscles controlling the poison glands forcing the venom out. 
This is not so. The poison is not expelled every time the snake 
gapes its jaws. 
Puff Adders frequently yawn, gaping their jaws widely. 
Sometimes both fangs are erected to their fullest extent. At 
other times, the snake raises and depresses them in turn. This 
is done carefully and deliberately, seemingly for the purpose of 
exercise. The occasional raising of the fangs evidently gives 
some measure of relief or satisfaction to the snake. It is rare 
for Cobras to yawn, except after a meal. The Adders do it at 
various times. 
When artificially feeding Puff Adders, venom frequently 
squirts from the fangs when the mouth is forced open and the 
fangs erected. In these cases, the reptiles are naturally in a 
state of irritation. This causes the constriction of the glands 
the instant the fangs assume the erect posture. At these feeding 
times I have collected as much as eleven drops of venom from a 
single Puff Adder. 
Care has to be exercised at feeding times to hold the snake’s 
head in such a position that the fangs point away from the faces 
of the operators. My assistant one day received a full charge 
of venom over his mouth, moustache, and chin. Luckily, none 
entered his eyes, else there would have been trouble. 
