220 THE INVISIBLE WORLD 



One member of the family has the disease and 

 dies. All the other members are of course ex- 

 posed. One or more of them may be predisposed, 

 the others not. No immediate harm to any of 

 them. Years pass, and all is well. A dozen years, 

 or more, glide away, and the family is still happy. 

 No signs of infection yet. But, finally, the plague 

 develops in another member, and in that home 

 is another vacant chair. The first sorrow, though 

 not forgotten, is yet assuaged, healed. In no wise, 

 except by name, is the second sorrow supposed to 

 be connected with the first. Least of all, does any 

 one for a moment suppose that the second mem- 

 ber took the plague from the first. Oh no, it has 

 been too long! The plague comes, they know not 

 how. Certainly it is not " catching." It comes be- 

 cause it does come. That's all! 



A thousand times this incident is repeated all 

 over the world. A thousand times, with the same 

 conclusion. The slow development is a blindfold 

 to the origin. 



In Africa the disease known as the " sleeping 

 sickness " yearly dooms thousands upon thousands 

 to a premature grave. From it no one recovers. 

 It is caused by a germ communicated by the bite of 

 a fly. After the bite, it takes about four years for 

 the disease to show itself. When the natives are 

 told this, they cannot believe it. To them four 

 years hide the cause in oblivion. But if the effects 

 from the bite of the fly should come on as suddenly 

 as do the effects from the bite of the rattlesnake, 



