150 DISEASES OF THE HORSE’S FOOT 
bring it about. Thus, in an animal at grass, with, according 
to the weather conditions, an alternate moistness and 
dryness of the pasture, with its consequent influence on 
the horn secretion, these rings nearly always appear. The 
effects of repeated blisters to the coronet make themselves 
apparent in the same way, and testify to the efficacy of 
blisters in this region in any case where an increased 
growth of horn is deemed necessary. From this it is clear 
that the condition depends primarily upon the amount and 
condition of the blood supplied to the coronary cushion. 
Thus, fluctuations in temperature during a long-continued 
fever, or the effects of alternate heat and cold, or of healthy 
exercise alternated with comparative idleness, will each rib 
the foot in much the same manner. 
Treatment.—The condition is so simple that we may 
almost regard it as normal. Consequently, treatment of 
any kind is superfluous. Where constitutional disturbance 
is exerting an influence upon either the quality or quantity 
of the blood directed to the part, then, of course, attention 
must be paid to the disease from which it is arising. 
F, THE HOOF WITH BAD HORN. 
(a) Tue Brirritz Hoor. 
Definition.—As the name indicates, we have in this con- 
dition an abnormally dry state of the horn. 
Symptoms.—These are obvious. The horn is hard, and 
when cut by the farrier’s tools gives the impression of 
being baked hard and stony, the natural polish of the 
external layer is wanting, and there is present, usually, a 
tendency to contracted heels. With the dryness is a 
liability to fracture, especially at points where the shoe is 
attached by the nails. As a consequence, the shoes are 
easily cast, leading to splits in the direction of the horn 
fibres. These run dangerously near the sensitive struc- 
tures, giving rise in many cases to lameness. Even where 
pronounced lameness is absent the action becomes short 
