Fig. 1.—This is a typical case of Osteo Porosis, or Big Head, in a two-year-old colt. The bones of the face, lower jaw, and shoulder are greatly enlarged. The body has changed from a round barrel to a very flat-sided shape. The back is arched upward.

Fig. 2.-This cut shows the rounded condition of the face, due to enlargement of the bones of the face. subject is five years old, and in the early stage of the disease when photographed.

Fig. 3.-Represents the head of an animal that has made a recovery.(?) The bones of the fa

anlawead unt the lower jaw much thickened. Age eleven years.

Fig. 4. Shows the effects of the disease upon the bones of the leg while young. Both fore legs are crooked and not flexed. The animal made a recovery, and had a second attack at nine, producing an increased enlargement of the lower jaw and shoulder. Photographed at ten.

Fig. 5.