OSTEOPOROSIS. 259 



A high-heeled shoe (Fig. i, p. 27) is indicated in spavin lame- 

 ness. 



LEGAL ASPECT OF SPAVIN.— The fact that it is impossible 

 t(i draw a sharp line of demarcation between a " coarse hock " and 

 one with spavin, renders the subject of spavin a fertile cause of 

 dispute. Following the opinion held by Dick, Percivall, Barlow, 

 and Williams, among others, I think I may safely say that, if both 

 hocks are alike, the action perfect, and the power of bending the 

 joints unimpaired, a horse with coarse hocks should be passed 

 sound. In a case of slight spavin without impairment of action, 

 such as that mentioned on p. 256, an intending purchaser might 

 be recommended to buy, if the animal was otherwise suitable; 

 although I could not give a certificate of soundness ; for a bone 

 spavin (Watson v. Denton, see " Carrington and Payne's Keports," 

 vol. vii., p. 85) is an unsoundness, even when it does not produce 

 lameness. The fact of the existence of a spavin may naturally 

 be, and often is, a subject of contention. 



Osteoporosis {Big-Head). 



This appears to be a constitutional disease which manifests itself 

 by a swollen and porous condition of the bones, and by more or less 

 general paralysis. It is also known as osteomalacia, fragilitas 

 ossium, and mollities ossium. As little or nothing is known about 

 the nature of this disease, the names applied to it have no 

 scientific weight. A swollen and porous condition of certain 

 bones may be also observed in cases of actinomycosis (p. 125). 

 Although the term, osteoporosis, . is often applied to such a local 

 condition of bone, the use of this expression is restricted, for 

 convenience' sake, tO' the general disease at present under con- 

 sideration. 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," 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, i t is confined to Youn^ animalR ; althniigrh I have known 

 instances of nine or ten year olds having died of it. 



CHANCES OF RECOVERY.— My experience is that animals 

 affected with osteoporosis, and 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 stage of the disease. 



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

 months. Occasion allv, the period is two or three years. 



17* 



