28 Williams, Fisher, and Udall: The Spavin Group. 
CoNTRACTION OF THE Hoor. The contraction of the hoof has 
only been alleged to act in relation to one or, perhaps, two 
of the maladies, navicular disease and sidebones, and hence 
loses much of its interest to us in considering the etiology of 
the group. 
Even in the specified maladies the question is one of ani- 
mated’ controversy, some urging its causative importance, others 
denying it wholly and assigning it a position of effect instead. 
Certain it is that chronic navicular lameness is accompanied 
by contraction, but it is difficult to show that it causes the 
affection, if we look upon navicular disease as a separate malady. 
When considering navicular disease as one member of a great 
group, contraction and dryness of the hoof must be reckoned 
as a contributory or modifying cause rather than essential. 
Lavor. CONFINEMENT. The character of the labor or degree 
of confinement apparently exerts a profound influence upon the 
development of the affection. We have already referred to this 
in considering the influence of strain and concussion. In gen- 
eral, it may be stated as a rule that those animals are most free 
“9m these affections which are either regularly worked, whether 
moderately or severely, or enjoy the constant freedom of the 
open range or pasture, and that those are most vulnerable which 
are closely confined and kept in enforced idleness, worked inter- 
mittently, or put at work where they are driven but a brief time 
each day and kept standing hitched in a vehicle during long 
hours. 
In the free clinic of the New York State Veterinary Col- 
lege, where many of these observations have been made, it 
is found that numerous cases occur during April, May, and 
June. The farm animals in this community have little or no 
work during the winter months, and are generally kept closely 
stabled without exercise, on a limited diet of oats and hay, and, 
soon after being put to work in the spring, develop lameness, 
due to some member or members of this group. How con- 
finement may act prejudicially we do not know, but the clinical 
evidence of its influence is strong. The horse is preéminently 
an animal of action, and any severe restriction tends to lower 
his power of resistance to disease. This group of affections 
is generally considered the special heritage of city horses, which 
are constantly subjected to stabling, shoeing, and working on 
hard streets 
