DISEASES AND TREATMENT OF THE KORSE. 191 



troubled ag-ain. Watch that his kidneys are in good shape, and 

 have the animal exercised every day. If you have fear of a horse 

 becoming- attacked with this disease when you are going to drive 

 him let him walk easy for the first mile or so, and then he will be 

 all right. 



CHAPTER XX. 



DISEASES OF THE BONES. 



BIG HEAD (OSTEO-POROSIS). 



This disease is more common in some localities than others; 

 it is not met with much in Canada or Great Britain, but is fre- 

 quently seen in the United States and Mexico. It is a disease 

 which attacks horses from one to four years old, and rarely 

 attacks old horses, and it gradually comes on as the animal 

 grows, without any signs of soreness, only the bones of the head 

 and legs get larger and lighter and become very brittle, that is, 

 easy to break. Thus it gets the name "big." It more often affects 

 the bones of the head than those of any other part of the body. 



Causes. — it is difficult to say what is the real cause of this 

 disease, but it is supposed to be caused from an animal feeding on 

 pasture land deficient in the salts of lime. Some think it is 

 wholly caused from animals grazing on low-lying, swampy land, 

 where the grass grows long and does not contain the full amount 

 of nourishing substances. 



Symptoms. — At first the symptoms are not very well marked, 

 but the animal is noticed to be dull, fall off in condition, and his 

 muscles get very soft. The animal may run along this way for 

 four to six months, then the true nature of the disease will show 

 itself. The animal will seem stiff in traveling, his belly becomes 

 very gaunt, and the bones of the head will be noticed to be getting 

 larger than natural; then, after this, the bones of the legs may 

 also become enlarged, and as the disease goes on the bones will 

 continue getting larger, and the animal keeps gradually going 

 down in condition until he dies. In some cases the bones become 

 so brittle that while he his walking along one of his legs would 

 break and he would have to be destroyed. 



Treatment. — The treatment is not very successful, and if the 

 disease has been running on for any length of time it is best to 

 destroy the animal. If in the early stages, and he is on low 



