9* DIRECT INJURIES CAUSED BY INSECTS. 



taken from the diseased surface by another practitioner-. 

 And though Dr. Willan in his book speaks of the Aca- 

 rus as the concomitant of this disease, yet his learned 

 friend just mentioned observes, that he admitted that the 

 insect was not to be found in ordinary cases, and indeed 

 never seemed to have made up his mind upon the subject. 

 When I was at Norwich in 1812, Dr. Reeve very kindly 

 accompanied me to the House of Industry there, to ex- 

 amine a patient whose body was very full of the pustules 

 of this disorder ; but though we used a good magnifier, 

 we could discover nothing like an insect. I must observe, 

 however, that our examination was made in December, 

 in severe weather, when the cold might, perhaps, render 

 the animal torpid, and less easy to be discovered. 



From the above facts it seems fair to infer that this 

 animal is not invariably the cause of seabies, but that 

 there are cases with which it has no connexion. Now, 

 from this inference, would not another also follow, that 

 the disease produced by the insect is specifically distinct 

 from that in which it cannot be found ? Sauvages and 

 Dr. Adams are both of this opinion a , the former assign- 

 ing to it the trivial name of vermicularis ; and the latter 

 proving, by very satisfactory arguments, that it is different 

 from the other. If they were both animate diseases, but 

 derived from two distinct species of animals, (for it seems 

 not impossible that even our common itch may be caused 

 by an Acarus more minute than the other, and so more 

 difficult to find,) they would properly be considered as 

 distinct species ; much more, therefore, if one be animate 



a This opinion Dr. Bateman thinks probably the true one. Cutan. 

 Bis. 197. 



