TICKS. CHIGOE, AND SCORPIONS 297 



The tick transmits these diseases while sucking 

 the animal's blood, as the mosquito and tsetse 

 transmit malaria and sleeping sickness to man. The 

 microbes in all these diseases, being of the more 

 highly organized and animal variety, require two 

 hosts for their development, and pass one phase 

 of existence in each. 



In the case of the tick, it is the larval or six- 

 legged stage of the insect which, climbing on to 

 stalk of grass or herb, reaches its animal host, 

 and there develops maturity and two more legs 

 by feeding on the animal's blood. 



Sometimes these ticks attack man. I was 

 bitten in Angola, and even now, a year after, the 

 wound gives trouble, for its beak was left in, when 

 the tick was pulled off my finger. If I had 

 adopted the precaution of putting turpentine or 

 even vaseline on the tick, it would have loosened its 

 hold and itself removed its poisonous beak. 



While the ordinary tick causes man no more 

 than such occasional discomfort, there is one 

 variety, the Ornithodorus moubata, which carries 

 a spirillum, the cause of relapsing fever, a most 

 distressing disease. I never suffered from this 

 complaint in Angola, where it is rare, but was 

 infected in 1907, by the shores of Lake Banguelo, 

 and suffered from five short but sharp attacks of a 

 fever that caused me to be carried from the lake 

 for hundreds of miles through Northern Rhodesia 

 to the rail-head at Broken Hill; and twice left as 

 dying on the road by my terrified retinue. 



The Chigoe, or burrowing flea (Sarcophylla 

 penetrans), is found chiefly on the Angolan coast, 



