340 THE SNAKES OF SOUTH AFRICA. 
venom from six Puff Adders, viz. forty drops, was collected in 
a wineglass and mixed with raw meat. This the jackal at once 
ate. Whenever a Puff Adder was killed its poison glands were 
inserted into a bit of meat and given to the jackal. Puff Adders 
were allowed to bite dead birds freely, until the flesh was reeking 
with venom. These were fed to the jackal. 
Then we decided to apply the test. Surely, we thought, if 
swallowing venom will confer immunity, this jackal should be 
absolutely proof, for it had during the six weeks swallowed 
enough Puff Adder venom to kill a couple of hundred men. 
A Puff Adder was held by the neck and allowed to bite the 
jackal on the thigh: It bit twice, but only pecked. Refusing 
to bite again, we procured another and forced it to bite the same 
part of the leg, twice. We did not previously shave the hair, 
and although in each case the reptiles punctured the flesh, we 
noticed they shed a good deal of venom on the fur, and did not 
bite eagerly. One, two, three, four days went by and the jackal 
showed no outward symptoms of poisoning. It was as lively 
as ever, and ate as usual. No swelling was apparent. “I told 
you, Sir,” quoth my now jubilant assistant, “that the jackal 
would prove to be immune.” “No, I am not at all satisfied,” 
said I. ‘‘ There’s something wrong. Those snakes didn’t 
inject enough venom. Come along, we will make sure this 
time.” So we forthwith seized a big Puff Adder and levied toll 
on his store of poison. Measuring out three drops, I mixed it 
with about a teaspoonful of water and injected it by means of 
a serum syringe, into the muscles of the unbitten thigh of the 
jackal. A Puff Adder was allowed to give one quick bite, but 
was not permitted to hang on or worry the flesh. In five 
minutes’ time the jackal began to show symptoms of poisoning. 
In slightly less than one hour it was dead. 
Removing the skin from the thigh and cutting into the flesh, 
it was found to be charged with extravasated blood from the 
toes right up to the junction with the body. The whole flesh 
of the limb was saturated with blood, which had oozed through 
the walls of the blood vessels. The limb itself had swollen to 
three times its normal size. Opening up the body I found that 
blood had oozed out into the muscles covering the abdomen and 
ribs, giving them a patchy blood-stained appearance. The 
heart-muscles were also affected, small irregular red patches 
