DISEASES OF THE FETLOCK, ANKLE, AND FOOT. 441. 
‘Since ringbone is considered to be one of the hereditary diseases, no 
animal suffering from this trouble should ever be used for breeding 
purposes. . 
LAMINITIS, OR FOUNDER. 
Laminitis is a simple inflammation of the sensitive lamin of the 
feet, characterized by the general phenomena attending inflamma- 
tion of the skin and mucous membranes, producing no constitutional 
disturbances except those dependent upon the local disease, and hav- 
ing a strong tendency, in severe cases, to destructive disorganization 
of the tissues affected. 
Causes.—The causes of laminitis are as wide and variable as in any 
of the local inflammations, and may be divided into two classes—the 
predisposing and the exciting. 
‘Predisposing causes——From personal observation I do not know 
that any particular construction of foot or any special breed of horses 
is predisposed to this disease, neither can I find anything to warrant 
the assumption that it is in any way hereditary; so that while we 
may easily cultivate a predisposition to the disease, it does not origi- 
nate without an exciting cause. Like most other tissues, a predispo- 
sition to inflammation may be induced in the sensitive lamin by any 
cause which lessens their power of withstanding the work imposed 
on them. It exists to an extent in those animals unaccustomed to 
work, particularly if they are plethoric, and in all that have been 
previous subjects of the disease, for the same rule holds good here 
that we find in so many diseases—i. e., that one attack impairs the 
functional activity of the affected tissues and renders them more easy 
of a subsequent inflammation. Unusual excitement by determining 
an excessive blood supply, bad shoeing, careless paring of the feet by 
removing the sole support, and high calkings without corresponding 
toe pieces must be included under this head. 
Exciting causes—The exciting causes of laminitis are many and 
varied. The most common are concussion, overexertion, exhaustion, 
rapid changes of temperature, ingestion of certain feeds, purgatives, 
and the oft-mentioned metastasis. 
(1) Concussion produces this disease by local overstimulation.., 
The excessive excitement is followed by an almost complete exhaus- 
tion of the functional activity of the laminated tissues, the exhaustion 
by congestion, and eventually by inflammation. But congestion here, 
as in all other tissues, is not necessarily followed by inflammation; 
for, although the principal symptoms belonging to true laminitis are 
present, the congestion may be relieved before the processes of inflam- 
mation are fully established. This is the condition in the many so- 
called cases of laminitis which recover in from 24 to 48 hours. They 
should be called congestion of the lamine. 
