340 THE SNAKES OF SOUTH AFRICA. 



Adders were forced to bite a lump of raw meat, which was imme- 

 diately afterwards given to the jackal. On three occasions the 

 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 }")roof, 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 

 tinie." 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 



