312 DISEASES OF THE HORSE’S FOOT 
The serous matter exuding from the diseased keratogenous 
membrane appears, in fact, to be highly infective. Once 
its flow'is commenced, it slowly, but surely, invades the 
sensitive structures near it, appearing, as Blaine has put it, 
to ‘inoculate’ them. What is really the case, of course, is 
not that the discharge itself is infective, but that it is con- 
taminated with infective material. 
The fungoid-looking growths to which we have before 
referred are, in reality, nothing more than the villi of the 
sensitive frog and sole greatly hypertrophied and irregular 
Fic, 185.—Lower Asprct oF CANKERED Foot, SHOWING 
DESTRUCTION OF WALL. 
in shape. At times the hypertrophy is as a huge and 
compact enlargement occupying the position of the frog. 
Sometimes, however, it occurs as numerous elongated and 
twisted fibrous bundles, separated from each other by deep 
clefts, and the clefts filled with the offensive cankerous 
discharge (see Fig. 134). 
At a very advanced stage canker leads to destruction 
of much of the horny sole and frog; or even parts of the 
wall may become separated from the tissues beneath, and 
break away from the foot (see Fig. 185). At other times 
