262 DISEASES OF BONE. 



many cases — about 20 per cent, of the entire number^ — of osteo- 

 porosis. The young oolts and fillies had a fair supply of corn ; 

 but the grass was so coarse and innutritious as to be altogether 

 unsuitable for horse provender. Besides, it was grown on ground 

 which was small in extent, and had remained unchanged and 

 untilled for m.any years. 



This disease does not appear to be due to an insufficient supply 

 of corn ; for, all over the world, horses keep perfectly healthy on 

 grass alone, in countries where osteoporosis is unknown. Besides, 

 I have seen it appear in Ceylon, among young horses which had 

 been kept for several months previously, on- a very liberal 

 allowance of oats. Their grass, however, was coarse and rank. 

 It is instructive to note that the percentage of mineral matter 

 in good hay is at least double that in oats, and the percentage 

 in both cases is greatly affected by the nature of the soil upon 

 which the grass and corn are respectively grown. In either case, 

 the fodder will be abnormally poor in bone-forming material, if 

 it has been produced on land poor in lime. 



Deficiency in the amount of grass cannot induce osteoporosis ; 

 for thousands of horses in Egypt, Syria, Arabia, and other places 

 where osteoporosis is very rare, remain free from this disease ; 

 although for nine or ten months of the year, they get no grass ; 

 their only food being barley and barley straw. Also in South 

 Africa, where the disease is uncommon, many of the horses never 

 get either grass or hay ; only straw and Indian corn, or straw and 

 oats. Straw (see " Stable Management and Exercise ") contains 

 nearly as much mineral matter as hay. As horses in the open, 

 contract the disease as readily as those which are stabled, confine- 

 ment cannot be regarded as a cause. 



A^second cause^ s ugg-ested is residence in a damp situatio n, such 

 as a stable m a cellar, or on low ground. Pit ponies are specially 

 liable to this disease. 



The disease is n^ t . regarded a s due to diet, but wholly to climatic 



influences. It is very common in the Island of Hawaii, which 



furnishes at least 100 victims every year. Some parts of this 

 island of the Sandwich group are very damp, and have an annual 

 rainfall of about 150 inches. Other districts are dry, and are 

 rarely favoured with rain. In the former, the disease is remark- 

 ably prevalent, but it never occurs in the latter. Removal of 

 affected animals to a dry district is followed by immediate 

 improvement and ultimate recovery, which is a termination that 

 does not otherwise take place. Horses will contrac t it under a ny 

 c qnditions of diet, a.nd it sppma tn he regiilat.ed only by nlimaip 

 Altitude and temperature do not appear to affect the course of 

 the disease. Cases are seen both at sea level and on elevated 



