THE AMERICAN ENTOMOLOGIST. 



115 



of an animal which is incessantly biting the 

 skin, and thereby causing the patient to allay 

 the itching by scratching. They also explained 

 the contagions character of the affection by the 

 transference of the insects from one individual 

 to another. Because these discovorics were 

 (rue, they were denied and combated by the 

 medical writers of those days; yet nearly one 

 hundred and fifty yeai-s passed before any bet- 

 ter natural history of the mite appeared. King 

 frcorge II. "s physician. Dr. Hiehard Mead, of 

 London, I'eported Bnnomo and Cestoni's obser- 

 vations to (he Royal Society, and published 

 them in No. 2S:! of the "Philosophical Trans- 

 iictions." 



Wo have given this little historical sketch to 

 show how old the disease is, and how old a 

 knowledge of its cause is also. Notwithstand- 

 ing, from that (ime to this (1869) there has not 

 fixiled to exist medical men or naturalists who 

 deny the connection between the disease called 

 Itch and the Itch-mite. It is with medicine as 

 with everything else in the world— denial of 

 truth excites notoriety, so desired by the many. 



In view of what we have above said, it seems 

 impossible to conceive that a correct knowledge 

 of the Itch-mite should be, since Bouomo's 

 time, repeatedly lost in some of the great cen- 

 tres of medical teaching, (o bo again regained. 

 In 1812, a prize was offered in Paris for the dis- 

 covery of the little insect; and a certain apothe- 

 cary named Gales took it, by exhibiting before 

 a medical commission the Cheese-mite. Conse- 

 (juently those who searched patients with Itch 

 did not find this animal, and a prize was once 

 more offered; and Raspail showed the Cheese- 

 mite again, and, when the judges were satisfied, 

 proved it was such, and exposed Galas' dupli- 

 city. The cause of the Itch-mite had hencefor- 

 ward its adherents and opposers; whilst, in 

 various parts of the world, the lowest classes 

 understood it, and the melhods of its des(ruc- 

 tion: for ins(ance, (he old women in Corsica, 

 who picked them out with needles. Kenucci, 

 a native of the Island, probab'y familiar with 

 these old ladies' occupation, finally, in 18.S4, 

 taught the Parisian medical world how to find 

 the Itch-mite; and, from that time to this, the 

 insect and its ravages have been more thor- 

 oughly and scientifically sfudied, and the liter- 

 ature of the subject grown up into quite a der- 

 matological library. In 18+6, Dr. C. Eichstedt, 

 of Griefswald, and Prof. Kramer of Kiel, inde- 

 pendently discovered the male mite. We who 

 now-a-days, have treated the Itch disease, and 

 the natural history of the Itch-mi(c, naturally 

 feel as if we knew pretty much all about it; yet 



so late as 18-44, Prof. Hebra, of Vienna, gave 

 the German physicians a knowledge or a new 

 and terrible phase of this insect's habits and 

 habitats, in what is known as the Norwegian 

 Scabies, the first recorded ca?e having occurred 

 in that country. And so it probably will always 

 be in the ever-advancing science of medicine, 

 the present generation smiling at the errors and 

 ignorance of the preceding one. But when a 

 truth, like the one mentioned of Hebra's, is dis- 

 covered, then others are rapidly and constantly 

 being found to confirm it. Other cases were 

 soon reported by observers in Germany. 



We suppose, by this time, our readers want 

 to know a little mire about the insect itself, and 

 perhaps h.ave had hardly patience to read down 

 so far to learn about the strange-looking animal 

 heading our article. At present we include the 

 Itch-mite in the special class of Acarina, and if 

 our readers want to know more about the other 

 members of (his class, as (he Sugar-mite, the 

 Checse-mite, etc., we would refer them (o an 

 article in the September number of the Ameri- 

 can jSfatumlist, by our friend A. S. Packard, 

 Jr., who gives nnmorous and beautilul illustra- 

 tions, accompanied by pleasantly told descrip- 

 tions. Our article will fill up this chapter for 

 the Acarus scabiei, or Sarcoptes homini, or 

 Itch-mite. The animal is tortoise-shaped. The 

 head distinct from the trunk, with four pair of 

 jaws. Eight legs, four in front and four behind. 

 The larva has but si.x; legs. Beside the legs are 

 long bristles. The male differs from the female 

 in appearance, as to the bell-shaped suckers on 

 the ends of the legs, andalso isnot so large. This 

 insect has been found, not alone in man, but in 

 the skin of the horse, lion, lama, ape, Neapolitan 

 and Egyptian sheep, and the ferret. It has been 

 thought, also, that the mites found in many 

 other animals are the same as man's irritating 

 companion, their growth being favored or re- 

 tarded by their place of development, thus ac- 

 connting for the apparent differences in shape 

 and size. The Itch-mite lives in the skin, in 

 little passages dug by itself, or, sometimes 

 just beneath the epidermis or scarf-skin. 

 These burrows the animal extends into the 

 deeper layers of the epidermis, down to and 

 into the true skin, or rete mucosum, as it is 

 called. The Acarus moults three times, not, 

 however, specially clianging in form. The eggs 

 are oval in shape, quite large for the size of the 

 animal, and may bo laid by the female to the 

 number of fifty. We give here three drawings, 

 to show how the animal gets into the skin to 

 form the burrows, now called "acarian fur- 

 rows " bv dermatologists. 



