LICHEN". 673 



been recorded as occurrinfr in cattle and dogs ; and in books on 

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

 it result from the irrational administration of hydrargum cum 

 creta. 



(3.) LICHEN 



Is a papular form of eczema; 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 confined 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 

 appearance 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 papulse, giving to the leg an appear- 

 ance of being covered by the tails of rats. 



(4.) ECZEMA IMPETIGINODES, 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 

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

 epidermis. The purulent secretion, after its effusion, concretes 

 upon the broken surface, and produces yellowish laminated 

 crusts, often of considerable extent. When the crusts are rubbed 

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

 vivid crimson colour, partly concealed here and there by films 

 of whitish lymph, and secreting an abundant ichorous fluid 

 having a reddish tinge. This 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 the 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 affection often lapses 

 into the chronic form of eczema." — (Wilson.) 



