18 THE CANADIAN ENTOMOLOGIST, 



exceptions to this rule do exist, but for most that have occurred to me I 

 believe there is a reasonable explanation. For example, a single tick 

 may paralyse a sheep or cause serious lameness in a horse, but only 

 because the tick has chanced to insert its rostrum into particular tissues ; 

 in these cases, I have known the removal of the tick to afford almost 

 immediate and entire relief. 



An idea of this sort is at most a theory, but much support for this one 

 may be obtained by its satisfactory application. As to how it is that 

 various disorders, often of a serious and even fatal character, are induced 

 or rather follow the attack of particular insects, even in limited numbers, I 

 can only express the opinion that the effects are due, not to the primary 

 injury, but to the incidental transmission of an organism quite as foreign 

 to the attacking parasite as to its host. Thanks to American investigations, 

 scientific research has shown that the Texas Fever organism is transmitted 

 by ticks. I have affirmed this discovery in South Africa, and can add that 

 we have ticks innumerable and of the same species in non-fever districts 

 as we have where the fever is most prevalent ; and further, that ticks were 

 known in the present fever areas long before the disease spread into the 

 Colony. Major Bruce, by his labours in Zululand, has demonstrated that 

 the bite of the notorious Tse-tse Fly is only fatal because of the incidental 

 introduction of an infusorial parasite. Dr. Koch, I understand, is now 

 connecting malarial fevers with mosquitoes in an analogous association. 

 Ticks are the cause of sheep dying in Great Britain because they may 

 transmit to their host the bacillus of Louping 111. Other instances still 

 might be cited, but these I think are sufficient to impress one with the 

 fact that insects are often only unconscious agents, not principals, in 

 causing serious consequences through their bites. 



The simple bite of an insect varies in its effects with different subjects, 

 but, as Dr. Behr remarks, the variations seem due to personal idiosyncrasy. 

 A Kafir laborer, treading on an Acacia thorn, will simply grunt, and after 

 withdrawing it from his foot will go on unconcernedly with his work, 

 although it may have pierced his leather-like sole a full inch; a European 

 would be brought to the verge of tears, and might think himself incapaci- 

 tated for further work during the rest of the day. Just so a native is as 

 little annoyed with head-lice as a dog is with fleas, and sleeps soundly in 

 his squalid hut while bed-bugs carouse over his naked body. From the 

 vermin-seasoned, unfeeling savage to the super-sensitive product of civili- 



