DISEASES OF THE SKIN. 675 



Taeen recorded as occurring in cattle and dogs ; and in books on 

 skin diseases it is described as eczema mercuriale. T have seen 

 it result from the irrational administration of liydrargum cum 

 creta. 



(3.) LICHEN 



Is a papular form of ecaema ; the eruption, commencing as small 

 papules either isolated or confluent, and becoming excoriated, 

 discharges a serous fluid, which ultimately concretes into a 

 crust. This form is ccfnfined to the legs of horses, and situated 

 along the course of the flexor tendons. Sometimes all four legs 

 are affected, frequently one or two ; and from the peculiarity of 

 appearanee it gives to the 'legs the disease is known as "Eat 

 tails." This appearance is due to an exudation around the hair 

 follicles ; the hairs remain unchanged, except from friction, and 

 emerge from an elevated papulae^ giving to the leg an appear- 

 ance of being covered by the tails of rats. 



(4) ECZEMA mPETIGINODES, OR PUSTULOSUM. 



**In eczema impetiginodes the skin is highly inflamed and 

 swollen ; the vesicles, which in many places are aggregated into 

 confluent clusters, often communicate with each other, and form 

 a continuous vesicle of some extent. Their contents, at first 

 limpid, speedily become turbid and puriform, and in a short 

 speice of time are effused upon the surface by rupture of the 

 epidennia. The purulent secretion, after its effusion, concretes 

 upon the broken sarface, and produces yellowish laminated 

 crusts, often of conBiAarahle extent When the crusts are rubbed 

 off or removed, the exposed surface of the derma presents a 

 vivid cdnoson colour, partly concealed here and there by films 

 of whitish ]ymph> and secreting an abundant ichorous fluid 

 having a reddish tinge. Thia secretion hardens, if the inflamed 

 surface be exposed to the influence of the atmosphere, into a 

 thin dark-coloured scab, which remains, unless disturbed by 

 accident or design, until tlie excoriated surface is healed. 



"The eruption of eczema impetiginodes, as of the milder 

 forms of eczema, is successive ; fresh crops of pustular vesicles 

 are produced as the first decline, and in this way the disease is 

 prolonged, especially if irritated by the employment of injudi- 

 cious remedies. In the latter case the aflection often lapses 

 into the chronic form of eczema.*'— (Wilson.) 



