48 DIRECT INJURIES CAUSED BY INSECTS. 
Mouffet further notices the effect of warmth upon them in exciting motion.! 
Our intelligent countryman also observes that they cannot be Pediculi, since 
they live under the cuticle, which lice never do.* In the epistle dedi- 
catory, the editor speaks also of them as living in burrows which they have 
excavated in the skin near a lake of water; from which, if they be ex- 
tracted with a needle and put upon the nail, they show in the sun their 
red head and the feet with which they walk. And to close my veleran 
authorities, Junius thus explains the word Acarus, as I find him quoted in 
Gouldman’s useful dictionary, “ A small worm, which eats under the skin, 
and makes burrows in itching hands.”* 
In more modern times, microscopical figures have been added to descrip- 
tions of the insect. Bonomo first furnished this valuable species of eluci- 
dation. 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 corre- 
spondent, 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 Scaliei ; an 
opinion which he repeats in his late work on Cutaneous Diseases, and which, 
according to Hermann’, has been also rendered unquestionable by Wich- 
mann in his Ltiologie 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 occasional 
concomitant of scabies. 
This fact being ascertained, a more complex inquiry remains, which 
branches out into two distinct questions. Is scabies always produced by 
these insects? Or, if this be not the case, is the animate scabies a distinct 
disease from the inanimate ? 
It is very remarkable that Linné, a physician as well as a naturalist, 
and De Geer, one of the most accurate observers that ever existed, 
should both assign the insect in question as the undoubted cause of the 
common scabies of their country; the one applying to the disease he was 
speaking of the epithet of communissima, and observing the fact to be 
notorious (cuique liquet), and the other designating it by its well known 
French name, La Gale.8 And is it not equally remarkable that such 
1 Extractus acu et super ungue positus, movet se si solis etiam calore adjuvetur. 
Ubi supr. Ungui impositus vix moyetur; si vero oris calido halitu affletur, agilis in 
ungue cursitat, Jn. Suec. 1975. ‘ 
2 Neque Syrones “-ti sunt de pediculorum genere, ut Johannes Langius ex Aris- 
totele videtur assere._; nam illi extra cutem vivunt, hi vero non. Ui supr. 
5 Imo ipsi Acari prm exiguitate indivisibiles, ex cuniculis prope aque lacum quos 
foderunt in cute, acu extracti et ungue impositi, caput rubrum, et pedes quibus 
gradiuntur ad solem produnt. _p. vi. ; 
4 Teredo sive exiguus vermiculus, qui subter cutem erodit agitque cuniculos in 
pruriginosis manibus. Gouldman tells us these dcari were also called Hand-worms. 
Another Iinglish name is also given in Mouffet, viz. Wheale-worms. 
5 Osservazioni intorno @ pellicelli del corpo umano fatte dal Dottor Gio. Cosimo 
Bonomo, &e. f. 1—3. - Baker, On Microsc. 1. t. 13. f. 2. 
6 De Geer, vii. 4. 5. f. 12.14. 
7 Mém. Aptérologique, 79. 
8 1 am informed by my learned friend Alexander MacLeay, Esq., late secretary 
