OSTEOPOROSIS. 261 



also observed in cases of actinomycosis (p. 125), Although the 

 term, osteoporosis, is often applied to such a local condition of 

 bone, I restrict, for convenience sake, the use of this expression, 

 to the general disease which we are at present considering. The 

 characteristic swelling of the bones of the nose, owing to their 

 prominence and porous nature, attracts most attention ; hence the 

 popular designation " big-head," which is applied to this malady. 

 In fatal cases, the animal seems to die from exhaustion. It attacks 

 all classes, and both sexes of horses. As a rule, it is confined 

 to young animals; although I have known instances of nine or 

 ten year olds having died of it. 



CHANCES OF RECOVERY.— As far as my experience goes, 

 animals which are affected with osteoporosis, and which are kept 

 under the conditions that give rise to it, invariably die from it. The 

 only hopeful cases are those which are properly treated in an early 

 stajze of the disease. 



Fig. 99. — Pear-shaped firing iron. 



DURATION.— Fatal cases usually run a course of several months. 

 Occasionally, the period is two or three years. 



GEOGRAPHICAL DISTRIBUTION.— This disease appears to be 

 confined to no particular country. Although I have noticed its 

 occurrence, chiefly, in Eastern Bengal, Ceylon, Singapore, and 

 South China — all of which jilaces have a hot moist climate — 1 

 have seen a large number of cases (all confined to one stud farm) 

 in the native state of Bahawulpore in the Pimjab and a few in 

 South Africa, the climate of both of which countries is dry and 

 hot. To judge by the fact that Friedberger and Frohner describe 

 horses as suffering from rickets but not from osteomalacia (osteo- 

 porosis) ; this disease Avould appear to be very rare on the Conti- 

 nent. It is found in certain parts of North America, the Sandwich 

 Islands (Harold B. Elliot) and Australia (W. T. Kendall). 



SYMPTOMS. — I have remarked that the characteristic swelling 

 of the face appears midway between the upper corner of the 

 nostril and the eye (Fig. 100). The enlargement is dift\ise; though 

 fairly well defined. With very few exceptions in the cases I 



