DIRECT INJURIES CAUSED BY INSECTS. 81 



supposes (in which opinion Dr. Bateman concurs with him) that the 

 authors to whom he alludes had mistaken for lice some other species of 

 insects, which are not unfrequently found in putrefactive sores. 



If these observations be allowed their due weight, it will follow, that a 

 disease produced by animals residing under the cuticle cannot be a true 

 Phthiriasis, and therefore the death of the poet Alcman, and of Phere- 

 cydes Syrius the philosopher, mentioned by Aristotle, must have been 

 occasioned by some other kind of insect. For, speaking of the lice to 

 which he attributes these catastrophes, he says that " they are produced 

 in the flesh in small pustule-like tumors, which have no pus, and from which 

 when punctured they issue. "^ For the same reason, the disorder which 

 Dr. Heberden has described in his Comment aj-ies, from the communica- 

 tions of Sir E. Wilmot, under the name of Morbus peclicularis, must also 

 be a different disease, since, with Aristotle, he likewise represents the 

 insects as inhabiting tumors, from which they may be extracted when 

 opened by a needle. He says, indeed, that in every respect they resem- 

 ble the common lice, except in being whiter; but medical men, who 

 were not at the same time entomologists, might easily mistake an Acarus 

 for a Pediculus.^ 



Dr. Willan, in one case of Prurigo senilis, observed a number of small 

 insects on the patient's skin and linen. They were quick in their motion, 

 and so minute that it required some attention to discover them. He took 

 them at first for small PedicuU ; but under a lens they appeared to him 

 rather to be a nondescript species of PuIexP ; yet the figure he gives has 

 not the slightest likeness to the latter genus, while it bears a striking resem- 

 blance to the former. It is not clear whether his draughtsman meant to 

 represent the insect with six or with eight legs : if it had only six, it was 

 probably a Pediculus ; but if it had eight, it would form a new genus 

 between the Acarinaand the hexapod Aptera. Dr. Bateman, in reply to 

 some queries put to him, at my request, by our common and lamented 

 friend Dr. Reeve, relates that he understood from Dr. Willan, in conversa- 

 tion, that the insect in question jumped in its motion. This circumstance 

 he regards as conclusive against its being a Pediculus ; but such a conse- 

 quence does not necessarily follow, since it not seldom happens that insects 

 of the same tribe or genus either have or have not this faculty ; for in- 

 stance, compare Scirtes with Cyphon, small beetles, and Acarus Scabiei 

 with other Acari^ 



Dr. Willan has quoted with approbation two cases from Amatus Lusl- 

 tanus, which he seems to think correctly described as Phthiriasis. In one 

 of them, however, which terminated fatally, the circumstances seem rather 

 hyperbolically stated — I mean, where it is said that two black servants 

 had no other employment than carrying baskets full of these insects to 

 the sea ! ! Perhaps you will think I draw largely upon your cred ulity if 



' Hist. Animal. 1. 5. c. 31. 



2 From the terms employed by Aristotle and Dr. Mead in their account of these cases, it 

 appears that the animal they meant could not be maggots, but something bearing a more 

 general resemblance to lice. 



3 On Cutaneous Diseases, 87, 88. ; and t. l.f. 4. 



■• Latreille at first considered this as belonging to a distinct genus from the common mite 

 (Acarus domesticu.s), which he named Sarcoptes; but upon its being discovered that it also 

 has mandibles, he suppressed it (N. Diet. d'Hist. Nat. xxi. 221.) ; but it has been since 

 resumed by M. Duges and other authors. 



