310 DISEASES OF THE HORSE'S FOOT 



nately refractory to treatment, showing always a tendency 

 to spread to the other feet of the same animal, and often 

 to the feet of other animals near enough to become infected, 

 and always cured — when cured it is — by a treatment which 

 may be summed up in two words as ' rigid antisepsis.' 

 Other diseases, with points in common with this, have 

 been directly proved to be due to a specific cause. Common 

 regard for logic compels us to admit the same for canker. 



Fig. 134. — A Foot, the Subject of Canker, showing Destruction 

 of the Horny Frog, and a Fungoid-looking Hypertrophy of 

 the Tissues Beneath. 



Symptoms and Pathological Anatomy. — The symptoms of 

 canker are seldom noticeable at the commencement of an 

 attack. The disease is slow in its progress ; for some time 

 confines its ravages to the subhorny tissues, unseen, and is 

 quite unattended with pain. It is not observed, therefore, 

 until considerable damage has been done, and the disease 

 is far advanced. What is usually first seen is a peculiar 

 softening and raising of the horn of the frog. The in- 

 fective material has set up a chronic inflammation of the 



