642 OPERATIONS ON THE TOOT. 



traction is more marked, that is, behind, is either perpendicular 

 to the ground, or even oblique downward and inward, in such a 

 way that the coronary circumference is greater than the plantar, 

 and consequently it represents an inverted truncated cone. 



The opposite form of contraction, that of the coronary, is seldom 

 seen, and we may ignore it. The waU is irregularly rough and 

 ramy, and without its shining appearance. The heels are gener- 

 ally high, nearly as high as the toe, though it is not so severely 

 altered in cases where the heels only are contracted. As a con- 

 sequence of the contraction of the plantar border of the wall, the 

 sole seems to become folded in the direction of its antero-posterior 

 axis, and it shows a much greater concavity on its internal face 

 than in the normal state. This cavity is then filled by the frog, 

 considerably reduced in size, thus presenting an idea of the sever- 

 ity of the contraction. Most frequently it is a thin, thready body, 

 flattened on its sides by the closing of the bars; its branches, thin 

 and narrow, resembling two bands so closely resting on each other 

 that the lacunae which separates them is no more than a narrow 

 fissure, which wiU scarcely admit the introduction of the thin 

 blade of a knife, and from the bottom of which escapes a sero- 

 purulent, gray or blackish liquid ; the lateral lacunae being also 

 transformed into two narrow and deep fissures, fiUed with the 

 same fiuid. The bars, generally high, assume a direction perpen- 

 dicular to the ground, instead of being oblique, as in the normal 

 state, from the centre of the foot toward its circumference. 



In all the regions of the foot, but especially at the wall, the 

 horn is so dry and hard that sharp instruments cannot cut its cor- 

 tical covering, whUe it is at the same time brittle, and hence nu- 

 merous superficial fissures appear at the quarters, and the outside 

 and inside toes, the frog itself being hoUowed by fissures upon its 

 body and branches. Sometimes it happens that the bars show 

 deep fissures, running from above downward, to the extremity of 

 the lateral lacunse, which are thus continued by a crack of the 

 heel up to the skin of the coronary band. There is often a separ 

 ration of the wall and the sole, the formation of what has been 

 called a double wall, or false quarter. Quarter cracks are com- 

 monly met with it. Corns are frequently seen in connection with it. 



"Whatever may be the form of the contraction, it is generally 

 accompanied by pain, manifested by change of position whUe at 

 rest and by lameness when in. action. 



