816 



DISEASES A^^D THEIR TREATMENT. 



urc of the boiiu, rc2)resented. by Fig. 72U, happened near to the 

 point of the lever, Avhile being raised, under Aveight from behind, 

 upon the point. In the case under consideration the bone ]iad be- 

 come weakest on its inner half, precisely at the center line of the 

 foot, so depressed by its thinness that the foot tilted inward, and 

 gave way immediately beneath the pivot, the mid-line of the coi'o- 

 nary bone; this Avas also the fulcrum of the lever, the front of the 

 bone being its point of resistance. As in the former case, the rais- 

 ing of the foot from a 2)lane toAvard a AX'rtical line fractured the 

 corresponding bone in the two cases in difterent positions, but 

 through the same causes, — Aveakened hot)f. and tlir other adA'crse 

 conditions Avhich led to atrophy of the bones. 



Fig. 722 is a representation of a fractured naviculaj- bc;nr, a 

 casualty of more frequent occurrence to horses in this country than 



Yu:. 72:2. 



is commonly knoAvn, but Avhich has scarcely been noticed. Fract 

 ures of this kind arc eft'ects due entirely to long-protracted ad^ 

 verse conditions of the feet, such as have been already dwelt u[)oii. 

 I haA^e never met Avith a case of fracture of either colfin or navicular 

 bone Avhere ])i"evious long-prevailing diseased action of the foot Avas 

 not manifest. 



In the instance represented above, the reader may see that the 

 bone was exti'nsively ulcerated and cxcaA'ated like a decayed tooth, 

 and at last the fracture occurred in tAVO lines diverging fj-oni tlie 

 excavated center to the anterior margin of the bone, Avhere it, is 

 connected to the cotiin-bone. • But I must request the reader to go 

 back Avith me to see the order and se^iuence of occurrence; llie ex- 

 cavation of the miAucular bone is a secondary occuri-ence, an effect 

 due to preceding and continuous de\'iations from health. 



The coffin-bone in Fig. 722 is Avasted down (o about tw<>-lliir<ls 

 of its natural depth and substance. Its semi-lunar civst is gone; 

 there is no sufficient concaAdty behind the plantar surface of the 



