5i6 Veterinary Medicine. 



In certain cases the extent of the primary eruption is greater 

 from the first, or it extends through reinfection by combs, brushes 

 and rubbers used in grooming or by friction by the harness, the 

 affected skin is hot, painful, congested and thickened throughout 

 its entire substance, the pustules are much more numerous, often 

 confluent, and may even implicate the subcutaneous connective 

 tissue. The crusts formed on the sores may acquire a breadth of 

 I inch to ij^ inch. Considerable abscesses may be formed and 

 the lymph glands communicating with the affected part are hot 

 and swollen. Even after the opening and discharge of the ab- 

 scess, the base of the sore remains indurated and indolent, and 

 centres of softening and caseation may appear so that healing is 

 delayed for one or two months or more. In such cases extensive 

 cicatrices remain after recovery. lyymphangitis is a common 

 accompaniment with even abscess of the lymphatic glands. 



Diagnosis. From chafing and bruising by the harness, this is 

 easily recognized by its appearing also on other parts than those 

 covered by the harness, by the development of the characteristic 

 pustules, by its following a regular cycle of eruption and sub- 

 sidence covering a definite period of usually 15 days, and by the 

 indisposition to maintain itself indefinitely under the friction of 

 the harness. 



From horse pox it is distinguished by the habitual avoidance of 

 the common seats of election of that disease (heels, lips, nostrils, 

 buccal and nasal mucosae, lips of the vulva), by the absence of 

 hyperthermia, and by the comparative absence of the remarkable 

 amber-like concretions which characterize horse-pox in the lower 

 limb. 



From impetiginous eczema it is diagnosed by its contagious and 

 inoculable properties, by the absence of the early falling of the 

 hair from the circumscribed rounded nodules, and by the ab- 

 sence or moderate character of the pruritus which is usually in- 

 tense in the eczema. 



The eruption of urticaria appears much more suddenly, shows 

 no tendency to form vesicles nor pustules, is not inoculable, and 

 subsides often as suddenly as it appeared when the irritant food 

 materials have been expelled from the alimentary canal. 



From acute /ar([)/ it is distinguished by the moderate degree of 

 the implication of the lymph vessels and glands, by the white 



