DISEASES OF HORSES 305 



or of sugar of lead or oil of peppermint. A course of bitters (one- 

 half an ounce Peruvian bark daily for a week) may be serviceable 

 in bracing the system and producing an indisposition to the erup- 

 tion. 



SUMMER SORES FROM FILARIA IRRITANS. 



The summer sores of horses (Dermatitis granulosa, boils) have 

 been traced to the presence in the skin of another parasite, 3 milli- 

 meters in length and extremely attenuated (Filaria irritans Railliet) 

 The sores may be seen as small as a millet seed, but more frequently 

 the size of a pea, and may become an inch in diameter. They may 

 appear on any point, but are especially obnoxious where the har- 

 ness presses on the lower parts of the limbs. They cause intense 

 and insupportable itching, and the victim rubs and bites the part 

 until extensive raw surfaces are produced. Aside from such fric- 

 tion the sore is covered by a brownish-red, soft, pulpy material with 

 cracks or furrows filled with serous pus. In the midst of the soft- 

 ened mass are small, firm, rounded granulations, fibrinous, and even 

 caseated, and when the soft pultaceous material has been scraped 

 off, the surface bears a resemblance to the fine yellow points of 

 miliary tuberculosis in the lung. The worm or its debris is found 

 in the center of such masses. These sores are very obstinate, re- 

 sisting treatment for months in summer, and even after apparent 

 recovery during the cold season they may appear anew the follow- 

 ing summer. In bad cases the rubbing and biting may cause ex- 

 posure of synovial sacs and tendons, and cause irremediable injury. 

 Even in winter, however, when the diseased process seems arrested, 

 there remain the hard, firm, resistant patches of the skin with points 

 in which the diseased product has become softened like cheese. 



The apparent subsidence of the disease in winter is attributed 

 to the coldness and comparative bloodlessness of the skin, whereas 

 in summer, with high temperature, active circulation, and rapid 

 cell growth, inflammation is increased, itching follows, and from 

 the animal rubbing the part the irritation is persistently increased. 

 The hotter the climate the more troublesome the disease. The life 

 history of the parasite is unknown, but it probably enters the sys- 

 tem with the food or water. 



Treatment. Treatment consists in placing the animal in a cool 

 place and showering with cold water. The parasite may be 

 destroyed by rubbing the surface of the wound with iodoform and 

 covering it with a layer of collodion, and repeating the applications 

 every twenty-four hours for fifteen days, or until the sores heal up. 

 Ether or chloroform may be used in place of iodoform, being poured 

 on cotton wool and applied to the sore for two minutes before paint- 

 ing it with collodion. 



CRACKED HEELS (SCRATCHES, OR CHAPS ON KNEE AND HOCK). 



This usually sets in with swelling, heat, and tenderness of the 

 hollow of the heel, with erections of the hairs and redness (in white 

 skins), with stiffness and lameness, which may be extreme in irri- 

 table horses. Soon slight cracks appear transversely, and may gain 

 in depth and width, and may even suppurate. More frequently 



