When the periostitis and ostitis is the result of a wound, and is complicated by caries or necrosis of the bone, the diseased portion of bone must in every case be laid bare and removed.  It so happens that the majority of cases of this kind occur in positions where the diseased bone is easily got at.  The lower margin of the os pedis or portions of the wings are commonly the seat of such changes.  We meet with the former in cases of pricked foot, and with the latter in severe cases of tread, or as a complication in suppurating corn or in quittor.  In such cases the animal must be cast and the foot secured.  The wound is then followed up, the horn if necessary removed, and the bone curetted with a Volkmann’s spoon; or, if showing itself as a sequestrum, removed with a scalpel and a strong pair of forceps.  Care must be taken that every particle of the diseased bone is removed, and that no part of it is left to act as an after-source of irritation.  With removal of the diseased portion and a strict attention to antisepsis healing soon takes place.

Reported Cases of Periostitis and Ostitis.—­1.  ’Figs. 150 and 151 represent the phalangeal bones of the off fore-leg of a thoroughbred horse named Osman, who was well known as a hunt steeplechaser of considerable merit in the Midland counties some twenty years ago.  I may say that this horse was under my observation pretty regularly during the whole of his career, and up to the time of his death, from ruptured aorta, when eight years old.  My attention was called to him as a yearling by his owner, who told me that he sometimes fancied the colt was lame.  I went over to see him, and found that he was unmistakably lame on the off fore-leg.  Careful examination showed no heat or enlargement anywhere.  I advised rest and the colt became pretty sound, though not quite so—­in fact, he never did become quite sound, and sometimes he was very lame indeed.

[Illustration:  FIG. 150.—­EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR BONES.]

’Every imaginable sort of treatment was tried short of neurectomy, without avail.  The curious part of the case was that there never was much heat or any apparent change of structure, nor was “pointing” a very noticeable feature.  The foot always remained a good-looking one.  As the horse won a good number of races he was of some value, and was seen by a good many members of the profession, who were by no means unanimous as to the cause of lameness.  The favourite theory was that it was a sequence of “split pastern.”  A post-mortem examination showed that there was no fracture.  There was no adherence of the tendon to the navicular bone nor any ulceration.  The morbid changes consisted entirely of osseous deposit as shown in the photographs.  The under surface of the navicular bone was much enlarged and roughened by this bony deposit, which extended on to the os pedis, causing complete anchylosis at each extremity of the navicular.  The lateral cartilages were healthy.  The interesting points in connection with the case are the insidious commencement of osseous disease, its extensive development, and the entire absence of any external manifestation, through its being confined entirely within the limits of the hoof.