90 Mr. Clark's Appendix to a Treatise 



strange receptacles for their young. But we may remark, that if they did suc- 

 ceed in depositing their eggs in the human body, they are quite sure to lose 

 their labour, and their object would be frustrated by the removal of the larvae, 

 which the individual himself can do readily, or his surgeon would not fail to 

 do for him, so that the race must speedily become extinct if such were bestowed 

 upon them as their natural and proper nidus and place of deposit. 



In a late medical periodical, whose title I do not exactly recollect at the 

 moment, is a strong statement of a case of this kind, by the late Surgeon How- 

 ship, intended to establish the doctrine of the existence of a human CEstrus, at 

 page 1/4 of the number containing it, elaborately written, and assisted by my 

 friend Mr. John Curtis, of well-known entomological celebrity. The larva 

 there given, though much altered in appearance by being pulled out and 

 lengthened, and perhaps by a degree of putrefaction ere it was placed in spirits, 

 agrees in so many, if not all, particulars of make with the larva of CEstrus 

 Bovis, given in my plate, that there is little doubt of its being the same. I at 

 first imagined it might prove the larva of a Caterebra, whose parents are very 

 bold in respect of deposit, but a subsequent investigation makes me rather 

 refer it to the above. The sacculated appearance of the skin, and the double 

 rows of spines, are exactly as described by me, and other strong circumstances 

 leave little room to doubt of its being the above species, of all others the most 

 active in producing these misplaced phenomena. We may observe that the 

 cow's back is covered with hair ; and the human scrotum also (the part where 

 this specimen was found) being covered with hair, would the more readily in- 

 duce the deposit in this particular part, if exposed. Sometimes the eggs have 

 been laid in the skin of the human abdomen, the other parts above alluded to 

 being perhaps covered at the time and not exposed to the attack of the insect, 

 or they would probably have obtained a preference. 



Mr. Howship, in the above-mentioned communication, appears to have mis- 

 taken the tail of the larva for its head, as was very natural, that part being 

 largest and uppermost in the abscess. It is obvious that, had it been other- 

 wise placed, respiration would have been impracticable, as the head is down- 

 wards in the abscess for the purpose of receiving nutriment with the mouth, 

 surrounded with pus of ready access, and the anus, on the contrary, is placed 

 upwards, for the more ready ejection of the faeces out of the abscess, and is 



