746 
Foot-rot in Sheep* 
the explanation of numerous discrepant opinions tipon the subject of foot-rot 
in sheep. The observations which have been made during the last few years 
have established in the writer's mind the conviction that the foot of the 
sheep is liable to at least live distinct diseases, which are produced by inde- 
pendent causes, and in their earlier stages quite easily recognised by their 
characteristic features. One of the live affections generally comprehended 
in the term foot-rot is undoubtedly highly contagious. Another of them . . . 
can be propagated by the action of the morbid products of the disease, when 
all the conditions are favourable. The remaining three varieties are conse- 
quent upon mechanical influences, and only occur when those influences are 
in action. These conclusions, the truth of which now scarcely admits of a 
question, furnish at once an explanation of the great differences, which have 
been noticed by observers, in the characters presented by the diseased parts, 
and also of the contradictory opinions which have prevailed, as to the con- 
tagious nature of the malady." 
In discussing the diseases of the foot of the sheep, Professor 
Brown divides these into (1) those in which the hoof horn is 
primarily affected, and (2) those in which the hoof horn is 
secondarily affected. 
Under the first head he classes the following non-contagious 
forms : — 
a. That variety of which an illustration (fig. 2) Las already been given. 
It exists on sandy soils or upon clay lauds where much grit is mixed with 
the clay ; it prevails most extensively in wet seasons, but even during a 
certain dry summer occasional instances were met with. 
b. That variety dependent upon the overgrowth of the hoof-horn, which 
occurs particularly among sheep that have been removed from a bare upland 
pasture to a rich, soft, lowland turf. In this form the hoof is primarily at 
fault, and the derangement of internal structure is a result of the external 
changes. As in the variety previously noticed, however, when the malady 
is fully developed, every distinctive character is lost in the general morbid 
state of all the foot structures, and very frequently tho implication of 
adjacent parts. 
c. That variety arising from injuries inflicted from without. Punctures 
from thorns, wounds caused by projecting sharp stones, and occasionally 
the accidental introduction of a nail into the foot, may be followed by 
inflammation, and, if neglected, by the separation of the hoof from the 
secreting membrane, and the successive appearance of those changes of 
structure which are observed in foot-rot, as the term is understood. 
With reference to those forms of foot-disease in which the hoof- 
horn is secondarily affected, it is observed that sheep are un- 
doubtedly liable to at least one affection of the feet of a decidedly 
contagious character — that, namely, which is identical with foot- 
and-mouth disease in cattle. Another form of tho foot-disease, 
which may be distinguished as " contagious foot-rot," prevails 
on certain lands, and especially during wet weather. To in- 
vestigate the pathology of this disease an inquiry was undertaken 
in 1867 at the suggestion of the Maidstone Farmers' Club, three 
affected sheep being made the subjects of the experiment. 
In the early stage of tho disease those animals had the hoofs 
