FIGHTING INCIPIENT DISEASE 51 



see presently on the screen. The tsetse 

 fly, which you will also see, may be either 

 male or female. Both suck blood freely, 

 the tsetse fly being one of the very few flies 

 which does not lay eggs, but carries her 

 young and feeds them on blood till they are 

 through the larva and ready to enter upon 

 the pupa stage. I like to mention these 

 little points, because one of the most gratify 

 ing results of my former course of lectures 

 has been that I have received such interest- 

 ing letters from former members of the 

 regiment who have gone to other countries, 

 and are kind enough to write to me of their 

 experiences of fighting disease and of dealing 

 with accidents where surgeons are hopelessly 

 ungetatable. To know how disease is caused 

 is generally to avoid it, if you will take the 

 trouble. The Trypanosoma Brucei, which I 

 shall also show you on the screen, alive and 

 full of motion, is the cause of horse-sickness, 

 which those of you who have followed 

 history in South Africa must have read 

 much of. But this, I fear, is all wandering 



