[ 105 ] 

 * Let us obferve the effects of the weight of 

 the body upon the Tendo Achilhs in the fol- 

 lowing circumftances. 



If a horfe be fhod with cramps, then there 

 is a great dillance between the frog and the 

 pavement : the weight of the body bears upon 

 the cramps -, the frog which is now free in the 

 air yields downwards, the tendon is llretched, 

 and if the horfe makes a fudden violent motion, 

 the rupture of the tendon is almofl inevitable : 

 becaufe the frog cannot reach the ground 

 to eafe the tendon, to which it ought to be the 

 point of fupport j if the tendon is not ruptured, 

 yet the horfe will be lame a long time after, 

 becaufe of the great diftenfion of the fibres 

 which were fo much upon the ilretch as to be 

 near breaking. 



If we fet on fhoes with only flrong heels, 

 the frog is not fo high from the ground -, the 

 "weight of the body may indeed force the frog 

 to touch the middle of a paved (lone, and 

 thereby prevent the great diftenfion of the ten- 

 don ; but as the thicknefs of thefe heels hinders 

 the fubftance of the frog to bear upon the 

 ground, to yield and reftore itfelf as much as 

 it is capable of by its natural elafticity, the 

 tendon muft fnap, by any violent and fudden 

 fpring, every other circumftance being equal. 



But if a horfe is fhod without ilioe-heels, 

 the frog which bears all the horfe's weight 

 gives way at every Hep, and by its elafticity is 

 reftored to its natural Hate, the tendon is never 



dragged 



