DIRECT INJURIES CAUSED BY INSECTS. 45 



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 Pherecydes 

 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 tumours, which have no pus, and from which when 

 punctured they issue." 1 For the same reason, the disorder which Dr. 

 Heberden has described in his Commentaries, from the communications of 

 Sir E. Wilmot, under the name of Morbus pedicularis, must also be a dif- 

 ferent disease, since, with Aristotle, he likewise represents the insects as 

 inhabiting tumours, from which they may be extracted when opened by a 

 needle. He says, indeed, that in every respect they resemble 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. 2 



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 Pediculi; but under a lens they appeared to him 

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

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

 semblance 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 Acarina and 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 conver- 

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

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

 sequence 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 instance, compare Scirtes with Cyphon, small beetles, and Acarus Scabiei 

 with other Acari. 4 ' 



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

 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 credulity if I call 



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



2 From the terms employed by Aristotle and Dr. Mead in their accounts 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. 7. f. 4. 



4 Latreille at first considered this as belonging to a distinct genus from the com- 

 mon mite (Acarus domesticus*), which he named Sarcoptes ; but upon its being dis- 

 covered 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. 



