DIRECT INJURIES CAUSED BY INSECTS. 



69 



much for pure Phthiriasis, which term ought to be confined 

 to maladies produced by lice. I shall only further observe, 

 that as many species as exist of these, which are the causes 

 of disease, so many kinds of Phthiriasis will there be.^ 



Acari, or mites, are the next insect sources of disease in 

 the human species, and that not of one, but probably of 

 many kinds, both local and general. They are distinguished 

 from Pediculi not only by their form, but also often by their 

 situation, since they frequently establish themselves under the 

 cuticle. With respect to local disorders. Dr. Adams conjectures 

 that Acari may be the cause of certain cases of Ophthalmia. 

 Sir J. Banks, in a letter to that gentleman, relates that some 

 seamen belonging to the Endeavour brig, being tormented 

 with a severe itching round the extremities of the eyelids, 

 one of them was cured by an Otaheitan woman, who with 

 two small splinters of bamboo extracted from between the 

 cilia abundance of very minute lice, which were scarcely 

 visible without a lens, though their motion when laid on the 

 thumb, was distinctly perceived. These insects were pro- 

 bably synonymous with the Ciron des paupieres of Sauvages.^ 

 — Le Jeune, a French physician quoted in Mouffet, describes 

 a case, in which what seems a diiferent species, since he calls 

 them rather large, infested the white of the eye, exciting an 

 intolerable itching.^ Dr. Mead, from the German Ephe- 

 merides, gives an account of a woman suckling her child, 

 from whose breast proceeded very minute vermicles.^ These 

 were probably mites, and perhaps that species, which, from 

 its feeding upon milk, Linne denominates Acarus Lactis. 

 The great author last mentioned describes an insect, a native 

 of America, under the name of Pediculus Ricinoides, which, 

 upon the authority of Rolander, he informs us, gets into the 

 feet of people as they walk, sucks their blood, oviposits ^ in 



1 For further information on this disease, see the valuable Manual of Ento- 

 mology, by Dr. Burmeister, for an English translation of which we are indebted to 

 Mr. Shuckard (p. 307.), where, it is contended, but surely on inconclusive evi- 

 dence, that Pediculus tabescentium, Alt. {Dissertatio de Phthiriasis, Bounce, 1820) 

 is produced by spontaneous generation. 



2 On Morbid Poisons, 306, 307. 3 MoufFet, 267. 

 4 Medica Sacra, 104, 105. 



s It is to be hoped this new word may be admitted, as the laying of eggs can- 

 not otherwise be expressed without a periphrasis. For the same reason its sub- 

 stantive Oviposition will be employed. 



F 3 



