140 LECTURES. 



numbers. Armed, as most of them are, with 

 sharp bristles, or stiff hairs, their active movements 

 in the intestinal canal could hardly fail to be 

 productive of serious mischief. Occasionally, one 

 meets with the dead eggs of the common flesh-fly 

 in the faeces, these having been swallowed acci- 

 dentally at table after they had been thoroughly 

 cooked along with the joint on which the parent 

 insect had deposited them. The larvae of Diptera 

 are usually passed alive ; and three particular 

 examples, which Dr. Wilson Fox kindly sent me in 

 a pill-box, assumed their imago condition some time 

 after they had been placed in my cabinet. I hope 

 at no distant day to unravel some more of the 

 mysteries connected with the occurrence of these 

 spurious parasites in the human body, but I can 

 assure you that the subject is surrounded by many 

 difficulties. In this connexion I will only record 

 two other allied cases, as I must, for the present at 

 least, bring my remarks to a close. 



CASE LXXIX. J. H. W., a distinguished 

 clergyman, rather beyond middle age, requested my 

 advice respecting certain injuries received from the 

 bite of the common harvest-bug (Leptus autumnalis). 

 That these bites were not trifling may be gathered 

 from the fact, that their poisonous effects had 

 resulted in the formation of three large boils on the 

 surface of the abdomen. Their inflamed look 

 bespoke severe irritation at the surface, whilst as a 



