160 INDIRECT INJURIES CAUSED BY INSECTS. 



their skin ; not improbably the same species that in a 

 similar way attacks the latter, as I have stated above. 

 We have heard that the vaccine disease is derived from 

 the cow and the horse, and the small-pox is said to have 

 originated in the heels of the camel : but neither the in- 

 genious Dr. Jenner nor any other writer on this subject 

 has informed us that the rein-deer is subject to the dis- 

 temper last named ; yet Linne quotes the learned work 

 of a Swedish physician on Syphilis, who gravely gives 

 this as a fact a ! ! The inoculator, in truth, is the gad-fly, 

 the tumours it causes are the pustules, and its larvae are 

 the pus. — It is astonishing how dreadfully these poor 

 animals in hot weather are terrified and injured by 

 them : ten of these flies will put a herd of five hundred 

 into the greatest agitation. They cannot stand still a 

 minute, no not a moment, without changing their pos- 

 ture, puffing and blowing, sneezing and snorting, stamp- 

 ing and tossing continually ; every individual trem- 

 bling and pushing its neighbour about. The ovipositor 

 of this fly is similar to that of the ox-breese, consisting 

 of several tubular joints which slip into each other ; and 

 therefore Linne was probably mistaken in supposing 

 that it lays its eggs upon the skin of the animal, and that 

 the bot, when it appears, eats its way through it b : there 

 can be little doubt (or else what is the use of such an ap- 

 paratus ?) that it bores a hole in the skin and there de- 

 posits the eggs. About the beginning of July the rein- 

 deer sheds its hair, which then stands erect — at this time 

 the fly is always fluttering about it, and takes its oppor- 

 tunity to oviposit. The bots remain under the skin 



rum fauce, per nares intrans ! " confounding probably CE. vetermus 

 of Mr, Clark with the true CE. nasalis. 



* Lack. Lapp. i. 280, h Flor. Lapp. 79. 



