DISEASES OF THE FEET. 239 



earlier stage of navicular disease. Again, in contracted feet, the sole is 

 generally so much recessed that the frog hardly ever comes to the ground, 

 and hence, from want of use, it becomes diseased. 



Paring of the frog, independent of its injurious effect in removing 

 the frog from pressure, has also a further tendency to produce disease. 



Symptoms. — Foul smell and slight lameness. 



Treatment. — In the treatment of those cases which originate in dirt 

 and wet, first remove the cause and keep the frog scrupulously clean and 

 dry. Any ragged or partially detached parts should be removed with a 

 knife so as to open the cracks in and around the frog. 



Having removed the cause, endeavor to absorb the discharge. This 

 is essential, because the discharge is of an acrid nature, and has in itself a 

 tendency to cause disintegration of the structure. The absorption of the 

 discharge will be best effected by inserting pledgets of tow, greased with 

 an ointment of calomel: 



Chloride of mercury 3 i. 



Lard § i. 



in the cleft. The process of drying may also be assisted by the applica- 

 tion of: 



Sulphate of zinc 3 iv. 



Water 1 pint 



or powdered burnt alum. The crust at the heels should be bound so as 

 to bring constant pressure upon the frog. Keep the foot dry. 



"When the disease has its origin in navicular disease, grease, or some 

 habit of body, little more can be done than to keep the frog scrupulously 

 clean, and to dry up the discharge with the astringents, etc., just de- 

 scribed, as soon as it appears. 



If thrush is long neglected, the neighboring parts become affected, 

 and in bad cases the whole of the sensitive sole is involved. The sole is 

 then said to be " under-run; " or, in other words, the unhealthy secretion, 

 being greatly increased and unable to find sufficient exit through the in- 

 sensitive frog, burrows between the sensitive and insensitive sole. The 

 disease, if still further neglected, may run into canker. The treatment 

 of serious cases of neglected or chronic thrush is nearly similar to that- 

 required in canker. 



