386 DISEASES OF THE SKIN. 



part of the tissues do not undergo any liorny degeneration, but 

 rather a drying, mummifying process, covering the membrane in 

 the shape of numerous whitish, or white-gray scabs. 

 We recognize the following inflammatory conditions : 



Erythema. 



Erythema is the mildest form of inflammation of the cutaneous 

 membrane, and consists either of normal hypertemia of the corium 

 in its upper layers (erythema simplex), or it may be due to a slight 

 sero-eellular infiltration of the membrane of Malpighi (dermatitis 

 erythematosa). 



Etiology. Erythema originates as the result of various cuta- 

 neous irritations which may be mechanical, chemical, or thermic — 

 for instance, by friction of the collar upon the skin, by rubbing 

 together two cutaneous surfaces, by ether, oils, chloroform, tar 

 preparations applied to the skin, bites of insects, by ammoniacal 

 urine (in catarrh of the bladder), and by slight burning or freezing. 

 Erythema may also appear in connection with various cutaneous 

 diseases, such as eczema, scab, and canine varioloid. 



Clinical Symptoms and Course. The symptoms consist of 

 a bright arterial redness of the cutaneous membrane, which disap- 

 pears under pressure of the finger, but reappears immediately after, 

 and may be complicated by slight swelling in a few cases. As a 

 rule, the affected portion is reddened, but not irritable. The course 

 is usually short, depending to a large extent on the cause. When 

 this is suppressed erythema disappears, especially after the itching 

 and rubbing have discontinued, and in certain conditions by con- 

 secutive desquamation of the upper membrane. There is, how- 

 ever, a more or less dark-red spot left after the acute symptoms 

 of the disease have lessened. These finally disappear, but very 

 slowly. 



Therapeutic Treatment. There is not, as a rule, any great 

 irritation, It will be sufficient to remove the cause in order to 

 remove the erythema. If there is a certain amount of irritation, 

 we must lessen it by bathing the animal with cold water and 

 sponging the parts with any of the following solutions; lead- 

 water, ichthyol, or salicylic acid, soap, rubbing with salicylic oil 

 (1 part of salicylic oil dissolved in 35 to 40 parts of olive oil and 



