352 THE SNAKES OF SOUTH AFRICA. 
through some soft substance like sheet rubber loosely stretched 
over the mouth of a wine-glass, a limited amount of venom is 
shed, but that if the same snake is allowed to bite into the leg 
of a dead fowl or a lump of meat, and provided the reptile is 
allowed to grip like a dog and compress its jaws strongly, from 
two to six times the amount of venom is discharged, compared 
with the amount usually obtained by allowing the snake to bite 
through rubber or thin glazed cloth stretched over a glass. 
If a man be hungry and you give him a piece of dry cork or 
wood to bite or chew, little if any salivary fluid will flow into his 
mouth ; but if you give that same man a morsel of appetizing 
food to bite or chew, an abundance of saliva will flow, and the 
salivary glands will receive a powerful stimulus, and will instantly 
exert themselves to manufacture more saliva. So it is, in a 
sense, with venomous snakes. By the same pyschological in- 
fluence their venom glands, and the nerves which work them, 
are roused into intense activity when the snake, with malice 
intent, deliberately bites the flesh of an enemy or some substance 
which deceives him into that belief or which tends to impart the 
same feeling. 
Now and then when a snake lunges and misses his aim, the 
entire contents of the venom glands are shed, but in these cases 
the reptile has been wrought up to the highest pitch of excite- 
ment, and in the act of lunging the glands are compressed violently, 
there being no time to counteract the impulse imparted, as is 
the case with a man who aims a blow with his fist at some object 
which dodges just at the critical instant. The man is unable 
to counteract the command sent to the muscles of his arm to 
deliver a blow. 
When a snake is dead, the venom oozes from the fangs on 
the slightest pressure on the glands, and can be easily collected 
by elevating the fangs and compressing the venom glands. 
NATURE OF SNAKE VENOM. 
Cobra venom is a slightly acid fluid of about the same con- 
sistency as glycerine, and is very similar in appearance. Viperine 
venom is more watery than glycerine. However, on exposure 
to the air and light, it changes to a light straw-yellow colour. 
When exposed to the atmosphere it quickly dries and cracks 
