51 



IX. — On the Minute Anatomy of the Larva of Anthomyia canicu- 

 laris, Meigen. By Arthur Farre, M.D., F.R.S. 



Read April 28, 1841. 



The subject of the present memoir has come under my notice as a 

 parasite of the human body, of which, however, it appears to be a 

 rare inhabitant, as I have met with but a single instance of the kind, 

 and I believe there are only two or three similar cases on record. 



The mere circumstance however of this insect in its larva state 

 being found in the human intestine, it is not now so much my object 

 to record, as it is to bring before the Society a brief description of 

 the minute anatomy of this singular parasite, with a view of showing 

 the peculiar adaptation of its organs, particularly those of the diges- 

 tive system, to the circumstances in which it is thus occasionally 

 placed. 



The insect considered as a parasite appears to have its parallel in 

 the (Estrus or hot of the horse and sheep, and may perhaps be con- 

 sidered as constituting the bot of the human subject, though it does 

 not appear to be altogether limited to man, but has been also observed 

 to occur in the Boa constrictor.* 



The case which afforded me the opportunity of making the fol- 

 lowing observations was that of a rather sickly child, a girl 5 years 

 of age, who was brought as an out-patient to St. Bartholomew's Hos- 

 pital, in the month of June, 1837, having the ordinary symptoms of 

 irritation produced by worms, for which a brisk purgative was pre- 

 scribed. This had the effect of bringing away a vast quantity of the 

 parasites, which were stated to be alive at the time they were passed, 

 and were described by the parent of the child as coming away by 

 handfuls at a time, and which continued to be passed at intervals 

 for three weeks, when the case was lost sight of. 



A similar case occurred to Dr. Haviland of Cambridge, in the year 

 1836, in the person of a clergyman 70 years of age, who, after suffer- 

 ing disagreeable sensations about the epigastrium, which he described 

 as a tremulous motion, accompanied by loss of appetite and general 

 weakness, passed in the summer and autumn of the same year very 

 large quantities of the larvae, and, according to his own statement, 

 the chamber-vessel was sometimes half full, and he thinks that alto- 



* See Lancet, vol. ii. 1839-40, p. 638. 



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