80 MORBID PIIF.XOMF.NA COXN'F.CTED WITH 



Production of cavity of the hoof in chronic cases of navicular 

 illoibi'd spt'ci- disease. [The specimens, both healthy and diseased, 

 were here submitted to the inspection of the Society^ 

 It must be admitted, that the small pastern bone 

 in the diseased specimen is occupying rather more 

 the region of the leg than the area of the hoof, which 

 is the place Nature allotted for about two thirds 

 of its posterior division. The other disputed point, 

 viz, the elevation of the navicular bone and heels of 

 the coffin bone, must of necessity be conceded, pro- 

 vided I shew that the superior articulating surface 

 of the coffin bone is in close approximation with 

 the inferior articulating surface of the small pastern. 

 Morbid phono- jjj ^j^jg coustrictiou of tlic hoof and its contents, 

 matoryot the j|. ^^guld appear that their relative situations are no 

 fafse'^Josftion lougcr prcscrvcd ; that each constituent portion 

 oft'rehoof!"*'* encroaches on another; and that not one essential 

 division of this all-important member enjoys the 

 freedom of space as designed by the Creator. 



By reference to the diseased navicular specimens, 

 it will be seen that, in proportion as the small pas- 

 tern bone has suffered this protrusion or elevation 

 it necessarily conveys the superincumbent weight 

 almost exclusively to the coffin bone ; whilst the 

 upper articulating surface of the navicular bone, in- 

 stead of being opposed to the inferior and i^osterior 

 articulating surface of the small pastern, and catch- 

 ing the weight as a cup would a ball ; (his bone 

 appears to be lialf turned in its elevation, and to 



