SKIN DISEASES CAUSED BY INSECTS. 



689 



recommend hygienic care of the skin and frictions upon the upper 

 regions of the trunk with tar liniment, cresol or dikited carbolic 

 acid, solutions of asafoetida, and decoctions of walnut leaves. 



Hinrichsen is said to have found the larvse of the hypoderma in 

 the spinal canal of the ox. He thinks that the animals of the 

 bovine species ingest the eggs of the parasite with the food, and 

 that the young larvae reach the medullar canal by passing from the 

 stomach or intestine; they live in it for from five to six months; 

 they then emigrate in order to locate themselves under the skin. 

 They have, so far, been found but rarely in the rhachidian duct. 



In the dog, Railliet and Lenoir have mentioned lesions similar 

 to those occasioned by the hypoderma of the ox, and which are due 

 to the introduction under the skin of larvse of Ochromyia antlwo- 

 pophaga. These parasites give rise to the formation of hard, painful 

 tumors, which are of the size of a lentil to that of a nut, and pro- 

 vided with a central cylindrical opening, which becomes softened 

 within six or seven days, allowing the larvae to escape. They may 

 be found upon various regions, but especially upon the tail, ears, 

 and feet. The extraction of the larvae is the only efficient treat- 

 ment. 



Disease of the larvae of the Lucilia, which exists in 

 lambs, is especially found in Holland. According to Jennes and 

 Van Laer, it is due to the larvae of the Lucilia sericata. The 

 lucilia deposits its eggs upon the internal aspect of the thighs of 

 lambs, which are affected by diarrhea ; the larva seeks those parts 

 of the body where the wool is abundant (the base of the tail, lum- 

 bar region, etc.); it forms a sort of nest under the fleece and per- 

 forates the skin like a sieve. Adult animals are rarely affected. 

 The parasites must be removed and the skin given a lotion of a 

 carbolated solution or a decoction of tobacco ; these are the two 

 principal indications of the treatment. 



In tropical countries some meat-flies may occasion the death of 

 young animals of the bovine species. According to Frantzius,^ 

 2000 calves are said to perish every year as a consequence of in- 

 flammatory conditions produced by larvae of these flies upon the 

 umbilical region. 



The means directed against winged insects in general are fric- 

 tions with liquids having a very strong odor : cresol (2 per cent), 

 asafœtida (60 grammes dissolved in a glass of vinegar and two 



1 Frantzius: Virchow's Archiv, Bd. xliii. 



