ence of any external manifestation, through
its being confined entirely within the limits of the hoof.

[Illustration: FIG. 151.--EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR
BONES.]

'It should also be noted that the animal was able to undergo a severe
course of training for some years, and to gallop successfully over some of
the most trying courses in England. During the whole of this time he walked
and galloped apparently sound, but trotted always lame, and generally dead
lame.'[A]

[Footnote A: W. E Litt, M.R.C.V.S., _Veterinary Record_, vol. viii., p.
527.]

[Illustration: FIG. 152.--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.]

2. 'I herewith send you photographs of three cases of the above disease,
occurring in the internal surfaces of the wings of the os pedis. The photos
were kindly done for me by Dr. A. Lingard, Imperial Bacteriologist to
Government of India. It is a cause of many cases of obscure foot lameness
in India, and frequently accounts for the numerous entries on veterinary
medical history sheets under the heading "Contused Foot."

'The course of the disease is as follows: The disease makes its appearance
very soon after arrival in India, the animal being admitted to hospital
suffering with undoubted foot lameness, generally slight. One is soon led
to suspect this disease by negative symptoms of other disease being in
existence. No coronary enlargement or flinching on pressure to the coronet,
no shrinkage or wiring in of the heels, neither is the characteristic
pointing of navicular present. In the early stages one has false hopes
of recovery by finding gradual improvement for a time by fomentation and
poultices, followed by irrigation and stimulants to the coronet, and
perhaps the animal is discharged from hospital, to be returned after a
few days worse than ever. The disease then becomes insidious and more
pronounced, the nodding of the head, even at a walk, more exaggerated, and,
in fact, the animal seems afraid to put his foot to the ground, and much
resembles a horse with an abscess in his foot, either from prick or picked
up nail. He absolutely nurses his foot. There is a certain amount of heat
always present. The disease being now well developed, pressure is caused by
the ends of the navicular bone, and they become involved at their points
by bony deposits. The causes of this disease I attribute, firstly, to
hereditary predisposition; and, secondly the exciting cause, standing
confined o