646 
MUD-FEVER—CRACKED HEELS—GREASE. 
the presence of foreign material, interferes with regular healing, and 
leads to the formation of folds, cracks, and fissures. Chronic prolifera¬ 
tion then sets in around these, and leads to the formation in the 
hollow of the fetlock of thick cicatrices, which can only be removed by 
operation. 
During the inflammatory stage the animals go very lame, especially 
for the first few steps, but improve after a short time at exercise. 
Causes. Coarse-legged horses with long hair often suffer from this 
f 01 m of dermatitis when working on wet,ground. The epidermis is 
continually moistened, becomes macerated, and inflammation is then 
readily produced in presence of infectious substances. The absence of 
visible external cause, and the simultaneous appearance of disease in 
several feet, or in several animals in the same stable, gave rise to the 
idea that mud-fever was a blood disorder, and should be regarded either 
as a metastasis or as erysipelas. Joly and Truche regard it as contagious, 
although the specific organism is unknown. Truche seems to rely on the 
fact that the disease attacked several horses in a previously healthy 
stable aftei the introduction of some American horses suffering from it. 
The fact that the same causes were acting on a considerable number of 
animals at the same time was overlooked. 
Jenner declared equine grease to be identical with cow-pox. Since his time 
“protective grease” has even been spoken of, though neither Jenner’s 
experiments nor those instituted later in any way support this view. Many 
years ago it was denied by Leblanc, Deprato, and by other observers, and at 
the . present time no doubt exists that eczematous grease (mud-fever) is 
dissimilar to variola. It is even a question whether horse-pox can be included 
in the same category with grease. In France medical practitioners have 
claimed to have inoculated men with grease, and thus proved its variolous 
nature. But Leblanc pointed out the untenability of this view. He showed 
that the case of grease, from which inoculation was said to have occurred had 
been in existence for six months, and therefore could certainly not have been 
variola. The desciiption indicates the case to have been verrucous grease. 
Dieckerhoff has suggested that Bouley’s “protective grease” was probably 
stomatitis pustulosa contagiosa (horse-pox). Berger declares having seen 
grease pioduced in horses by inoculation with sheep-pox, but his observations 
do not appear very trustworthy. The attempts made in France to inoculate 
horses with cow-pox and cows with grease altogether failed. In the lio-ht of 
recent knowledge, it is easy to understand that the secretions found in the 
latter stages of grease produce inflammatory processes in man, but this in no 
w r ay demonstrates their specific character. There is little room to doubt that 
the earlier observers confused “ grease ” with horse-pox, an entirely different 
affection. Horse-pox is attended with fever, is very contagious, may affect 
an } portion of the skin, though it is often confined to certain regions or even 
° ne > an( l runs a comparatively simple, benign course, leading to recovery. 
When affecting the mucous membrane of the mouth and lips it constitutes the 
above-mentioned stomatitis pustulosa contagiosa. The confusion that has 
arisen between different writers owing to the loose use of the word “ grease ” 
lenders it desirable that either the w r ord be limited to the chronic verrucous 
form or that it be altogether abandoned in favour of the word “dermatitis,” 
