270 DISHASES OF THE HORSE’S FOOT 
any rate of the outer layer of the periosteum, is in laminitis 
constant even, we repeat, in a mild case. 
When the case is a serious one we have ample evidence 
Fig. 118.—SHowine CHANGES IN THE Os PrpIs witH Laminitis oF Lone 
STANDING, (a, Viewed from the front; 6, viewed from the side.) 
The porous condition of the bone, which is here shown, is a result of a rare- 
fying or rarefactive ostitis. This specimen also illustrated (what the 
photograph cannot show) an accompanying condition of condensation of 
bone, or osteoplastic ostitis, (For a fuller description of the changes 
oceurring in these forms of ostitis, see Chapter XI.) 
to show that ostitis exists, and exists in a severe form. 
The bones become vastly altered in shape, a process of 
absorption leads to the formation of large, irregular cavities 
within their substance, and what of the bone is left is 
