72 



DIRECT INJURIES CAUSED BY INSECTS. 



that they cannot be Pediculi, since they live under the cuticle, 

 which lice never do.^ In the epistle dedicatory, the editor 

 speaks also of them as living in burrows which they have ex- 

 cavated in the skin near a lake of water ; from which, if they 

 be extracted with a needle and put upon the nail, they shew 

 in the sun their red head and the feet with which they walk.^ 

 And to close my veteran authorities, Junius thus explains the 

 word Acarus, as I find him quoted in Gouldman's useful dic- 

 tionary, " A small worm, which eats under the skin, and 

 makes burrows in itching hands." ^ 



In more modern times, microscopical figures have been 

 added to descriptions of the insect. Bonomo first furnished 

 this valuable species of elucidation. His figures, however, 

 which are copied by Baker in his work on the microscope, are 

 far from accurate.'* Those of De Geer and Dr. Adams are 

 much more satisfactory, and mutually confirm each other.^ 

 From them it is evident that the same insect inhabits the 

 scabies of Sweden and Madeira. Dr. Bateman, in the letter 

 before alluded to, informs his correspondent, that he had seen 

 that from Madeira, and gives it as his opinion, that there 

 cannot be a doubt of the existence of an Acarus Scabiei ; an 

 opinion which he repeats in his late work on Cutaneous Dis- 

 eases, and which, according to Hermann has been also ren- 

 dered unquestionable by Wichmann in his Etiologie de la Gale 

 (Hanovre, 1786), a work I have not had an opportunity of 

 consulting. From all this we may regard the point as so far 

 settled, that an animal of this kind exists at least as an occa- 

 sional concomitant of scabies. 



This fact being ascertained, a more complex inquiry remains, 

 which branches out into two distinct questions. Is scabies 



1 Neque Syrones isti sunt de pediculorum genere, ut Johannes Langius ex 

 Aristotele videtur asserere : nam illi extra cutem vivunt, hi vero non, uhi supr. 



2 Imo ipsi Acari prse exiguitate indivisibiles, ex cuniculis prope aquae lacum 

 quos foderunt in cute, acu extracti et ungue impositi, caput rubrum, et pedes 

 quibus gradiuntur ad solem produnt. p. vi. 



3 Teredo sive exiguus vermiculus, qui subter cutem erodit agitque cuniculos in 

 pruriginosis manibus. Gouldman tells ns these Acari were also called Hand- 

 worms. Another English name is given in MoufFet, viz. Wheale- worms. 



4 Osservazioni interna d pellicelli del corpo umano fatte dal Dottor Gio Cosimo 

 Bonomo, &c. /. 1 — 3. Baker, On Microsc, i. t. 13. /. 2. 



5 De Geer, vii. t. 5,f. 12. 14. 



6 Mem. Apterologique, 79. 



