468 CHAPTEE 62. 



almost cease to exist. There is no fear of the frog wearing away, if ex- 

 posed to wear. The contrary is the invariable result. 



The frog has three principal uses, which it will only fulfil well if it be 

 large and prominent. The frog is an elastic pad intended first to receive 

 on itself a large portion of the jar and concussion which results from the 

 movement of so large carcassed an animal as the horse ; and again, by 

 receiving it on itself, it diminishes concussion in other parts of the frame, 

 such as the bones and joints, which are not by nature adapted for sus- 

 taining jar and concussion. Secondly, the frog being elastic and wedge- 

 shaped, acts as a stay to the ground against slipping. Hence its main- 

 tenance and development are objects of great importance. Thirdly, the 

 frog, when properly developed, acts as a support to the coffin-joint, espe- 

 cially to the centre of the navicular bone. 



Memo. I have said above that the frog ought not to be pared at all. 

 This is true in theory and correct in practice as regards a sound, healthy 

 frog. But all frogs are not sound and healthy. Disease, most commonly 

 thrush, is very soon set up in the frog by any carelessness, such as not 

 carefully and frequently washing out the feet, and especially by allowing 

 the horse to stand in his own dung or urine. Disease commences in 

 the frog, not in the outer layer, but under it, i. e. in the interior layer. 

 Hence it is often not discovered until it has run to a considerable extent. 

 Therefore it is a wise precaution in all cases, where there is any doubt, 

 as indicated by raggedness or unpleasant smell, to remove the ragged 

 parts with a view of ascertaining whether any disease is latent under- 

 neath. Such removal of the ragged parts ought not, however, to be 

 made an excuse for paring down the frog; nor is any such removal 

 allowable, unless there are at least some indications of latent disease. 

 The frog especially requires to be kept not only clean but dry. 



953. Cleanliness. 



One other point remains to be. considered, namely, cleanliness. Clean- 

 liness is essential to the health of the foot. The foot must be kept clean, 

 not only by washing and picking it out, but more especially by keeping 

 the stall clean and free from dung and urine. Stalls cannot be kept 

 clean unless the paving and drainage are good. Stables, I may add, are 

 seldom kept clean and sweet, unless in addition to good paving and 

 drainage there is also ample light and ventilation. 



951 Shape of the Foot. 



The shape of a good Foot (fig. G) at its lower or ground surface ap- 

 proaches that of the circle. The crust should grow down at an angle of 

 between 50 and 52 degrees (A, fig. 1). 



The ground surface has doubtless been made circular, because that 

 form affords within a given circumference a greater weight-bearing space 

 than any other. Other circumstances, however, require a slight modifi- 

 cation of the circular form. The continuity of the- circle is somewhat 

 broken at the heels by the insertion of- the wedge-like frog, and anteriorly 



