276 DICTIONARY OF THE VETERINARY ART. 



Spasm. An involuntary and continued contraction of mus- 

 cles ; thus lockjaw depends on a spasmodic contraction of 

 muscles. 



Spavin. A disease of the horse's hock, which generally 

 causes lameness. Spavins are of two kinds : the bone, and 

 the bog, or blood spavin. The former consists of a bony 

 enlargement of the inside of the hock joint, towards the 

 lower part ; the latter, of a soft, but elastic tumor towards the 

 bend of the joint. Mr. Percival remarks, " Notwithstanding 

 our confessed inability to cure this disease, we are often 

 called on to treat it, as to the removal of it by means of a 

 chisel, file, or saw. Although the practice is exceedingly com- 

 mendable in cases of common exostosis, it is not so well 

 adapted to spavin j those who employ such means seldom fail 

 to leave the parts ultimately in a worse state than they found 

 them. Our most successful remedies are such*as come under 

 the denomination of counter-irritants." 



Spermatic Cord. The vessels, &c, by which the testicles 

 are suspended, consisting of the spermatic artery and vein, 

 the vas deferens, or seed duct, cremaster muscle, and cellular 

 membrane. 



Sphincter. A name given to muscles whose fibres are 

 arranged in a circular direction, and whose office is to shut 

 up the parts to which they are attached ; such are the sphinc- 

 ter of the neck of the bladder, and the muscles which close 

 the fundament. 



Spine. The spine of the neck and back is composed of 

 many small bones named vertebras. Seven belong to the neck, 

 eighteen to the back, six to the loins, five to the sacrum, and 

 in the tail there are about thirteen. 



Spleen, or Milt. A soft substance, of a long, oval form, 

 and purple color. It seems to be a reservoir for the blood 

 that may be designed for the secretion of bile in the liver. 



Splents. These are bony excrescences, which grow on 

 the inside of the shank bone. 



Staggers. This is named from the staggering gait of the 

 animal. It may be brought on by the horse eating too greedily, 



