CHAPTER Xm. 



DISEASES OF THE BONES. 



X- BIO HSAD and big jaw. 11. 8WEBNT OF THB SHOULDER. 111. SWEKKT OV THK 



HIP. IV, BONK SPAVIN. V. ENLARGED HOCK. VI. RING-BONS. VII. STIFLK. 



^VIII. SPLINT. IX. SORE SHINS (INFLAMMATION OP THE METACARPAL BONB). 



X. ROTTEN BONB. XI. INFLAMMATION OP THE KNEE-JOINT. XU. CARIES OF THB 



LOWER-JAW. 



I. Big Head and Big Jaw. 



Causes. — This disease, called also exostosis of the bones, is manifested in 

 an enlargement or bony tumor on the face, on a line between the nostril 

 and the eye. It finally breaks out in small holes, which discharge a thick 

 pus, and at last ends, if not t'">s\ted opportunely, in a complete decay of 

 the bone. The bone continually enlarges, and cells or channels are 

 formed aa the minute bony plates become thinner and thinner, till the 

 structure can be easily cut with a knife or crushed with the fingers. The 

 interstices are filled with a red, bloody mass. In some cases the ligaments 

 and tendons are separated by decomposition of the bone, and crumblings, 

 dislocations and fractures take place for want of firm attachment for 

 these supporting ligaments. 



The primary cause of the disorder is not known ; but the tendency is 

 believed to be transmitted . A horse manifesting signs of the big head 

 is generally diseased not alone in the bones of the face, but the whole 

 osseous system seems to be to some extent involved, so that there is not 

 infrequently a soreness of the limbs and a lameness accompanying it. 

 The immediate exciting cause is most probably defective nutrition — a 

 want of that power of assimilation which is necessary to the supplying nf 

 the bones with their phosphate constituent. 



It may be developed by both over-feeding and by deficiency of food, as 

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