480 BOARD OF AGRICULTURE. 



This boDf is from such a knee-8prung joint and the disease in 

 question is an exostosis, a regular fungoid growtli of bone on the 

 outside ; it Ux)ks like a spavin and has been called a spavin of the 

 forward kuee. The disease that gave rise to this formation was an 

 •ossific inrtammation, or one attended with the deposit of bony mat- 

 ter. It is such an inlhunmaiion that produces the real spavin ; but 

 Ihere is no ditierence in the two forms oi disease, only different 

 joints are affected. This ossific type is hereditary, and knee-sprung 

 horses not unfrequently have a very great enlargement on this joint. 



Tliat disease is very common, and is caused in a large degree by 

 carelessness, in driving horses rapidly down hill and while there ia 

 an effort to hold back the load. Such efforts have a tendency to ere- 

 iite weakness in that joint. You often see a watery infiltration there 

 which is the same disease that is known in the human race as ''white- 

 swelling." A knee-sprung horse is not a promising subject for treat- 

 ment. Care in shoeing will do good in some cases, and it is well 

 to feed your horse from the floor and not from a high rack. Compel 

 him to feed from the ground, and he is obliged to throw these for- 

 ward legs back in order to get his head down. That etfort will often 

 be exceedinolv l)eneficial, and decolorized iodine is a valuable 

 4iniment when freely applied. This disease is a permanent blemish 

 and must be regarded as an unsoundness in every case. 



The three bones below this joint are very marked, and of such a 

 <;haracter that vou want to remember them. The laro^e bone in the raid- 

 •die is the cannon and the two little ones behind are known as splints. 



COMPARATIVE MORPHOLOGY. 



Now you want a little morphology, which is the science of torm, 

 and treats of resemblances and differences iu structure. Morpho- 

 logically speaking, m\' hand represents the horse's fore foot, and the 

 cannon bone is the metacarpal to which the middle finger is attached, 

 the two splint bones therefore correspond to the metacarpals of the 

 rinsr and fore fingers. The fetlock joint of the horse's fore foot cor- 

 responds to our great knuckle. The upper and lower pastern and 

 cofHn bone of the horse are homologous to the upper, middle and 

 4ower bone of the middle finger. The coffin bone was thus named 

 because it fits into the hoof so perfectly. The hoof corresponds to 

 the nail. The bottom of the foot is the end of the finger. The frog 

 ihas no representation in the human hand ; it is a new developed 



