260 DISEASES OF BONE. 



of the slieathes of the tendons are punctured. A firing needle 

 should be heated each time before it is used, so that its apiDlica- 

 tion may not cause either infection or putrefaction. After the 

 punctures are made, the part should be covered with an antiseptic 

 (p. 67). If necessary, the horse can be cast. He should be put 

 in slings, should remain in his box or stall for at least a month, 

 and should be kept on green grass, or on hay and carrots. As 

 the chief seat of the disease is in the interior of the bone or bones, 

 deep puncture firing gives far better results than line firing, or 

 firing with a pear-shaped iron (Fig. 99). Blistering and perios- 

 teotomy are rarely of any use in spavin lameness. 



It is advisable before firing to rest the horse for a few days, 

 and cool him down with green food, and Epsom salts (p. 609). As 

 the principle of puncture firing is to excite violent inflamma- 

 tion in the part, so as to promote the bony union of the diseased 

 surfaces; rest as complete as possible should be given after the 

 operation, until the completion of the desired union, which would 

 be retarded or altogether checked by movement. Hence the ad- 

 visability of using slings. 



A high-heeled shoe (Fig. 4, p. 27) is indicated in spavin lame- 

 ness. 



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

 to 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 bend- 

 ing 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, I would recommend an 

 intending purchaser 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 Reports," 

 vol. vii., J). 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) 

 appears to be a constitutional disease which manifests itself by 

 a swollen and jiorous condition of the bones, and by more or 

 less general paralysis. It is also known as osteomalacia, fragilitas 

 ossimn, 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 



