26 ON THE NAVICULAR DISEASE. 



obscurity, and consequently is too often speculative. 

 But with respect to the probable causes of the dis- 

 ease in question, I think there is as much light 

 elicited by the dissection of the morbid specimen as 

 we could desire. Commencing with the ground 

 surface of the horny frog, and unfolding, layer by 

 layer, all parts, until we arrive at the carious sur- 

 face of the navicular bone, there will be presented, 

 at one view, that which not only fully explains all 

 the phenomena of the disease, but suggests to us the 

 method of cure, and even points to a rational mode 

 of shoeing. 



I beg to observe, that in my former paper I un- 

 dertook a sort of classification of contraction, or ra- 

 ther its division into two kinds ; the one under the 

 designation of simple or general contraction, such 

 as the narrow-heeled foot with lengthened toe, so 

 very prevalent, and obvious to the common observer; 

 and which is frequently seen unaccompanied with 

 lameness, and even sometimes remains harmless 

 throuoh a lono; life of hard work. The other I have 

 called the occ?(/^ or ^jar//a/ contraction, which is one 

 of the most insidious diseases to which the horse is 

 sprcioiis np- subject ; and so specious is the exterior of such a 



pparaiiccs of ' , . 



fcoiiie hoofs, loot, tliat none but a most experienced eye would 

 discover the existence of any disease, unless at- 

 tracted to it by an accompanying lameness ; cir- 

 cularity, solidity, compactness of fibre, and an un- 

 usual appearance of strength, being its characteiis- 



