156 HEALTH AND DISEASE 



NEW FORMATIONS 



Of the diseases included in this group, i.e. cancer, lupus, and rodent 

 ulcer, the first is the only one which is recognized in the horse. The disease 

 in that animal is of rare occurrence, and usually affects the internal organs. 

 It can scarcely be referred to, therefore, as a skin disease. 



HEMORRHAGES 



Extravasation of blood into the superficial layer of the true skin is 

 described as purpura. The hemorrhage occurs as a consequence of some 

 change in the composition of the blood, excessive pressure of blood in the 

 small vessels, or impairment of the functions of the nerves which regulate 

 their calibre. The lesions or blood-stains in the skin may be in the form of 

 spots, small or diffused patches, or marks which look like bruises. The dis- 

 coloration, it should be noticed, is the result of diffused blood and not 

 merely of congestion. Pressure applied to the latter completely removes 

 it, but it does not remove the discoloration by blood when extravasated. 

 As the cause of the extravasation is some serious derangement of the 

 system, the disease is not to be dealt with by local remedies. (See Purpura 

 Hsemorrhagica. ) 



NEUROSES 



The diseases which are included in this division are increased sensibility, 

 diminished sensibility, and perverted sensibility. The last of these is 

 known in the horse as pruritus, which is really, as the word indicates, itch- 

 ing without any recognizable cause; there is no detectable eruption nor any 

 redness save what may result from the part being scratched, in fact itching 

 is the only symptom which has to be dealt with by remedies. In many 

 cases the itching is so excessive that in the language of the groom the horse 

 is driven nearly mad, and in his excitement he tears his clothing, and 

 increases the irritation by rubbing or scratching, causing an eruption and 

 erosions in various parts of the body. 



The treatment of the disease, which is necessarily associated with general 

 systematic derangement, belongs more properly to the domain of general 

 medicine, but for the alleviation of the annoying irritation local remedies 

 are indispensable. Dr. James Law of the Cornell University recommends a 

 wash of water slightly soured with oil of vitriol, and rendered sweet by 

 carbolic acid. If this acid lotion fails to afford relief, an alkaline and seda- 

 tive mixture may be employed instead for example, 2 drachms of carbonate 

 of potash and 2 grains of cyanide of potassium in 1 quart of water. It 



