MITES, TICKS, AND OTHER ACARI. 



509 



common assertion that living forms are a matter of course in every- 

 tliincj that we eat and drink is without warrant. While it is true that 

 water and one or two other articles usually contain microscopic or- 

 ganisms, the idea commonly conveyed by such statements is erroneous. 

 These degraded and disgusting forms are not proper food-stuiF; nor is 

 their consumption unavoidable. Pure ai'ticles, in an undamaged con- 

 dition, do not contain them ; and their presence in numbers in any 

 article of food is proof that it is unfit for human use, and should be 

 rejected. 



There are several species, placed by later authors in the same 

 genus with the sugar-mites, whose normal habitat seems to be on food, 

 insect collections, and in the dust and mold of cellars and damp 

 places, but which, when transferred to animal bodies, become para- 

 sitic, causing curious and painful disorders. Signor Moriggia figures 

 a singular horny excrescence which grew from the hand of a lady. 

 It was nearly eight inches long, tapering upward from a wide base, 

 and curved toward the wrist. Its 

 cavities were swarming with a spe- 

 cies of acari. Another species was 

 found by Heriug in the hind feet of 

 a horse, that, although young and 

 in other respects sound, had to be 

 killed. The hoofs were quite dis- 

 organized, the frog and sole con- 

 sisting of a soft, fibrous mass, se- 

 creting an offensive liquid ; in the 

 end, the sore spx-ead to the flexors 

 and muscles of the fetlock. A 

 negro inmate of the Seaman's 

 Hospital, Loudon, suffered from 

 large and peculiar sores on the 

 soles of the feet. Examination 

 by Prof. Busk revealed the pres- 

 ence of a mite, which was doubt- 

 less the cause of the trouble. The 

 negro attributed the disease to 



wearing a pair of shoes which were lent for a few days to another 

 negro who was similarly afflicted. The latter came from Sierra Leone, 

 and inquiry proved the existence of a pustular disease, native to that 

 place, called craw-craw, a species of itch very troublesome to cure. 



The genus Cheyletus is a very remarkable type. It is unquestion- 

 ably carnivorous, its palpi being adapted for holding its prey. They 

 are not gregarious in their habits; but, like all animals that live by 

 rapine, are solitary. When placed in company with the cheese-mites, 

 they seize them between their palpi, and, plunging their beaks into 

 the body, suck up the juices. The C. eruditus (Fig. 8) appears also 



Fig. 8.— Chetxetus erdditcs. 



