• DISEASES OF THE SKIN. 673 



fluid resembling' that contained in the vesicles. After the 

 disease has existed some time, there is a thickening of the 

 derma, which becomes corrugated, more especially in those parts 

 of the body where the skin is itaturally loose and moveable. 



The individual vesicles of eczema do not last long, and in. 

 some cases no vesicles are found ; but the skin is inflamed, and. 

 fissures make their appearance in the epidermis. These fissures 

 are at first superficial, but become deeper if the disease con- 

 tinues. This form has been called by Dr. Buchanan eczema' 

 Hmosum ; and in the horse it affects the flexures of the knees' 

 and hocks, termed respectively mallenders and sallenders, by 

 horsemen and farriers. Eczema characterised by fissures is' 

 generally a chronic form of the disease, and when affecting the^ 

 limbs it has been, designated by Greve, Psai-iasvi carpi et tarsi.. 



VARIOUS FORMS OF ECZEMA. 



(1.) ECZEMA SIMPLEX, HUMID TETTER^ 



A non-contagious disease, usually commencing about the neck, 

 shoulders, back, and thighs. It usually comes on suddenly, and' 

 is manifested by itchiness, which causes the animal to rub and 

 bite itself until the hair and cuticle are brought off, leaving 

 the skin red, raw, and inflamed. Successive crops of vesicles 

 develop themselves, dry on the sore skin, or discharge a fluid 

 which seems to cause an extension of the disorder. The parts 

 of the body most usually affected are those which are covered 

 by the saddle or harness ; but it may affect any part, such as 

 the/ head, neck, quarters, thighs, and fore-arms. It is generally 

 called mange, but it differs from true scabies in two essential 

 particulars, namely, it is not contagious, and does not depend 

 upon the presence of a parasite. 



Eczema simplex is sometimes very troublesome and difficult 

 to treat. In some horses it occurs periodically, or when an 

 alteration is made in the diet. As a rule, it is a summer disease, 

 prevailing in the warmer months ; but in a few cases which 

 have come under my notice, it has been developed in the winter 

 only, and when the horses were clipped. These are very 

 exceptional and peculiar cases, clipping in other instances 

 favouring the disappearance of the disease. Eczema siranlex 



