MUD-FEVER—CRACKED HEELS—GREASE. 
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(8) A gangrenous, including “cracked heels.” 
(4) A verrucous form (“ grease ” proper). 
The first three follow on acute inflammation of the skin, which, how¬ 
ever, may be attended with complications, and may later assume a 
chronic course. The last form, which is usually chronic, is that generally 
recognised in England as “grease” proper. Dollar believes that it is 
often preceded by the erythematous and exanthematous forms, but, as 
these are of short duration and infection of the discharging surfaces 
almost immediate, the red-blush of the skin (erythema) and the watery 
discharge (eczema) only last a very short time, and are speedily merged 
into the chronic condition, with offensive discharge and formation 
of warty growths, which English veterinary surgeons recognise as 
“ grease.” 
(1) Dermatitis erythematosa. This is the mildest form of dermatitis, 
and is commonest in horses with thin, fine skins ; well-bred animals 
suffer more frequently than heavy working-horses. In many horses the 
skin of the pastern-joint seems exceedingly sensitive, so that even the 
presence of sand in soft soils may cause irritation, and give rise to this 
form of dermatitis. Similar results have been noted after long-continued 
exposure to direct sunlight. The unpigmented skin appears red and 
rather painful, but after a few days these symptoms disappear, and 
active desquamation sets in. The disease consists of hyperaemia of the 
papillary layer of the skin, produces no permanent injury, and only 
occasionally requires special treatment. When, however, the condition 
is neglected, and the horse continues to work, this form of dermatitis 
may give rise to the next in order. 
(2) Dermatitis eczematosa. Mud-fever. Eczema, or inflammation of 
the skin, appears spontaneously, is ushered in with swelling and redness, 
is usually soon followed by exudation from the surface, and in general 
takes a typical course, which, however, is less easily studied in this 
position than in others. The swelling and redness are often scarcely 
visible, though there is lameness, especially when the animals are first 
moved, whilst the surface of the skin becomes covered with a yellowisli- 
red fluid, which soon dries to a brownish crust. The papular stage is 
not well marked, though the vesicular stage, i.e., the formation of small 
bladders, may sometimes be noted. The weeping stage (stadium 
madidans) appears more distinctly, and is rapidly succeeded by the 
formation of crusts (stadium crustosum). The crusts soon loosen under 
proper treatment, and desquamation follows (squamous stage), revealing 
normal epidermis. In characteristic cases the process takes eight to 
fourteen days, and ends in complete recovery, but not infrequently 
complications occur, especially if the animals are worked during the 
disease. The movement of the skin produced by walking, assisted by 
