DERMATITIS 15 



few days, and this is often the first symptom that attracts attention. The epi- 

 dermis of the patch falls off at the same time as the hairs; it appears to be 

 softened, and the surface of the skin has then a dark-grey tint and is slightly 

 moist, which might be attributed to the rupture of vescicles, though their pres- 

 ence has never been demonstrated. It cannot, therefore, be said, as Raillet 

 remarks, that the disease presents itself in the form of herpes, as what is so 

 called in human pathology includes a phase marked by the appearance of 

 vesicles. The humidity of the patch is ephemeral. Its surface generally soon 

 dries, and is covered with epidermic scales of varying thickness, which are 

 agglutinated into flat crusts that are shed and renewed incessantly. These 

 crusts have more frequently than in the ox a shinning appearance and a grey 

 or yellowish color like flax. At the same time, the lesion progresses by per- 

 ipheral extension until it attains the diameter of a five-shilling piece or more, 

 and on each zone invaded, successive symptoms are observed. Pruritis is nearly 

 absent in Microsporosis, and is scarcely even shown to exist, except by move- 

 ments indicating satisfaction on the part of the animal when the patches are 

 gently scratched. 



"2. Trichophytosis (Sporotrichum). A. Trichophyton flavum. The 

 lesions consist of large patches, at least 8 to 10 cm. broad, of a more or less 

 regular form, greyish, and quite smooth. The hairs, raised and matted at their 

 base by a greyish-yellow crust, fall away very rapidly with the crust. The 

 naked surface is not prominent, and shows no trace of suppurative folliculitis 

 (Bodin). 



"B. Trichophyton equinum occurs usually in numerous patches, some isolat- 

 ed, scattered over the croup and shoulders, and attaining at the most 3 cm. 

 in diameter. At first they can be detected only by touch, but later they become 

 visible by the flattening of the hair. The least traction or slight friction carries 

 off a scaly crust which brings away the diseased hairs. The skin then appears 

 smooth, moist, pinkish, or light grey. Very soon the patch becomes dry, scaly, 

 or powdery, and at its base a slaty grey. The lesions spread by the falling out 

 of the marginal hairs (Matruchot and Dassonville). 



"C. Trichophyton verrucosum, var. equi, occurs in numerous patches which 

 average 5-6 cm. in diameter, and are localized on the shoulders, neck, withers, 

 flanks, in fact, everywhere where the harness touches. By their confluence, 

 these patches may produce large, irregular lesions. At first the hairs are raised, 

 not broken, and are matted together at the base by a soft grey crust. This 

 crust falls off in less than a week, carrying away the hairs, and having an 

 absolutely bald, grey surface covered more or less with dry, greyish scales, and 

 without follicular suppuration. In young horses, however, the shedding of the 

 crust leaves a vesicle or pustule, then the surface of the patch is slightly raised, 

 red, and indurated (Bodin). 



"D. Trichophyton verrucosum, var. asini. The lesions are the same as in 

 the preceding Trichophytosis of the Horse, but are generally confined to the 

 neck, head, and ears (Bodin). 



"E. Trichophyton mentagrophytes. This Trichophytosis occurs usually on 

 the nostrils or head. It forms patches up to 5 or 6 cm. in diameter, which may 

 be mistaken for pustules of horse-pox undergoing regression. Over the whole 

 of these patches the hairs are matted together at their base by a soft, brownish 

 crust of unequal thickness. Slight traction on the hair brings away the crust, 

 exposing a bare, slightly raised surface, which is red, inflamed, and pitted with 



