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in the process as iu a vice of conformation wbicb, as is well Iruown, ia 

 liliely to be transmitted from parent to offspring. The faults of con- 

 formation most likely to be followed by the development of navicular 

 disease are an insufficient plantar cushion, a small frog, high heels, ex- 

 cessive knee actiou, and contracted heels. Finally, the environments 

 of domestication and nse, such as dry stables, heavy palling, bad shoe- 

 ing, punctured wounds, etc., all have their influence in developing this 

 disease. 



8i/mptonis. — In the early stages of navicular disease the symptomg 

 are generally very obscure. When the disease begins in inflammation 

 of the navicular bone the animal points the affected foot while at test, a 

 time before any lameness is seen. While at work he apparently travels 

 as well as ever, but when placed in the stable one foot is set out in front 

 of the other, resting on the toe, with fetlock and knee flexed. After a 

 time, if the case is closely watched, the animal takes a few lame steps 

 while at work, but the lameness disappears as suddenly as it came and 

 the driver doubts if the animal was really lame at all. Later on the 

 patient has a lame spell which may last during a greater part of the 

 day, but the next morning it is gone ; he leaves the stable all right, but 

 goes lame again during the day. In time he has a severe attack of 

 lameness, which may last for a week or more, wlien a remission takes 

 place and it may be weeks or months before another attack supervenes. 

 Finally, he becomes constantly lame, and the more he is used the greater 

 the lameness. 



In the lameness from navicular disease the affected leg always takes 

 a short step, and the toe of the foot first strikes the ground, so that 

 the shoe is most worn at this point. If the patient is made to move 

 backwards the foot is set down with exceeding great care, and the 

 weight rests upon the affected leg but a moment. When exercised he 

 often stumbles, and if the road is rough he may fall on his knees. If 

 he is lame iu both feet the gait is stilty, the shoulders seem stiff, and 

 if the patient is made to work he sweats profusely from the intense 

 pain. Early in the development of the disease a careful examination 

 will reveal some increased heat in the heels and frog, particularly after 

 work ; as the disease progresses this becomes more marked until the 

 whole foot is hot to the touch. At the same time there is an increased 

 sensibility of the foot, for the jjatient flinches from th€ percussion of a 

 hammer lightly applied to the frog and heels, or from the pressure of 

 the smith's pincers. The frog is generally shrunken, often of a pale 

 reddish color, and at times it is affected with thrush. If the heels are 

 pared away so that all the weight is received on the frog, or if the same 

 result is attained by the application of a bar shoe, the animal is exces- 

 sively lame. The muscles of the leg and shoulder shrink away, and 

 often tremble as the animal stands at rest. After months of lameness 

 the foot is found to be shrunken in its diameter and apparently length- 

 ened ; the horn is dry and brittle and has lost its natural gloss, while 



