DISEASES OF THE BONES 391 
fession, 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 adher- 
ence of the tendon to the navicular bone nor any ulcera- 
tion. 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 
Fig. 151.—Errects oF PERIOSTITIS ON THE PEDAL AND NaVICULAR 
Bones. 
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 in- 
teresting points in connection with the case are the 
insidious commencement of osseous disease, its extensive 
development, and the entire absence‘of any external mani- 
festation, through its being confined entirely within the 
limits of the hoof. 
