NAVICULAR DISEASE. 333 



non-paring of the foot, destroying its elasticity (Coleman) ; a 

 shoe thick at the toe, causing increased resistance to the action 

 of the flexors, and rendering the perforans tendon hable to 

 strain (Dick) ; thin-heeled shoes, by throwing the weight and 

 concussion on the posterior parts of the foot and frog, bruising 

 the synovial membrane ; hereditary tendency ; bad shoeing ; 

 bad nailing ; want of exercise ; too much exercise, &c. 



I. Contraction of the Foot. — Messrs. Turner and Percivall 

 wrote, that "of contraction there may be two kinds. Ist. A 

 contraction of the heels, called lateral contraction; 2d. Con- 

 traction of the hoof from below upwards, or veHical contraction ;" 

 and these were said by Professor Coleman to be the cause of 

 this lameness. He maintained that " expansion of the hoof 

 is effected by pressure upwards of the frog, and pressure down- 

 wards of the navicular bone. By properly thinning of the 

 sole, rasping the quarters, lowering the heels, giving the frog 

 pressure, and keeping the horse in a pond all day, or else tied 

 up with his lame feet in a tub of water, we have no difficulty 

 in removing contracted hoofs. Although difficulty there be 

 none, however, in restoring the original form of the hoof, 

 we too frequently find we have gained nothing by it, because ' 

 we have not restored the original structures of the parts con- 

 tained wdthin the hoof. Contraction of the hoof in consequence 

 of the internal parts being squeezed produces inflammation of 

 the laminae, and ossification of them. This causes the horse, 

 in galloping, to avoid to his utmost coming down upon his 

 heels, or to tread upon hard ground ; the concussion at such 

 times being great from loss of elasticity in the laminse, so that 

 the moment he comes to work he falls lame. In nine cases 

 out of ten of what are termed ' groggy * or ' foundered ' 

 horses, these parts, in consequence of chronic inflammation, 

 become altered in structure ; effusion of lymph or bony matter 

 taking place." I have thought it expedient to make this 

 extract from Coleman, in order to show the kind of pathology 

 taught by him ; and I hope to be able to point out the mischief 

 brought about by it — conclusions and generalities without one 

 fact to support them. 



Contraction of the hoof is not a cause, but an effect, of 

 disease ; an atrophy of the structures contained within the horny 

 box consequent upon diminished functional activity and adapta- 



