DIRECT INJURIES CAUSED BY INSECTS. 89 



you to act as you please. — Thus much for pure Phthi- 

 riasis, which term ought to be confined to maladies pro- 

 duced 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 distin- 

 guished 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 dis- 

 orders. 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 be- 

 tween tlie cilia abundance of very minute lice, Avhich 

 were scarcely visible without a lens, though their mo- 

 tion, when laid on the thumb, was distinctly perceived. 

 These insects were probably synonymous with the Ciron 

 des paupieres of Sauvages''. — Le Jeune, a French phy- 

 sician quoted in Mouftet, describes a case, in which 

 Avhat seems a different species, since he calls them 

 rather large, infested the white of the eye, exciting 

 an intolerable itching''. — Dr. Mead, from the German 

 Ephemcrides, gives an account of a woman suckling her 

 child, from whose breast proceeded very minute ver- 

 raicles''. These were probably Acari, and perhaps that 



' On Morbid Poisons, 306, 307. " Mouffet, 267. 



* Mediat Sacra, 104, 105. 



