26 OPERATIVE TECHNIQUE. 



without shock or pain in a horizontal position. The animal ma\' be 

 placed at any dej^'ree of inclination to the horizontal, and its position on 

 the table is extremely safe. Broken back has never occurred within 

 the writer's expt-rience. 



Methods of Casting. — A permanent bed is usually prepared 

 with six to eight inches of dry spent tan bark, covered with a 

 thick layer of short cut straw. Many practitioners still prefer the 

 straw bed to mattresses, because it is softer and because it can be re- 

 moved, and fresh straw supplied after each operation, whilst the mattress 

 must be thoroughly cleansed and disinfected. It has also the advan- 

 tage of being cheap, as clean straw is readily obtainable and may 

 afterwards be used for bedding, whilst it is a difficult matter for 

 veterinary surgeons in country practice to convey a mattress from 

 place to place. • Nevertheless, straw makes a very bad bed for 

 operations requiring careful antiseptic precautions, and wherever 

 possible should be replaced by a mattress covered with tarpaulin, 

 or by a proper operating table, though some of the disadvantages 

 of the straw bed may be overcome by covering it with a large 

 tarpaulin before casting the horse. Even so high an authority, 

 however, as Professor Bayer still adheres to the straw bed, pre- 

 ferring it partly because he has to teach students who, in practice, 

 would be unable to afford an operating table, and partly because 

 of the success attained in his own clinique. In support of his 

 recommendation he adduces a long series of cases in which the 

 wounds left by removal of shoulder abscesses, necrotic lateral carti- 

 lages, etc., healed by primary intention after suturing. 



To prevent internal injuries, like rupture of abdominal viscera, the 

 animal should fast or only receive light food for several hours before 

 operation, though, as already mentioned, this precaution is not abso- 

 lutely indispensable. Needless to say cases calling for puncture of the 

 bowel or bladder must not be cast. Should it be absolutely impossible 

 to perform the operation in the standing posture the operator 

 should wait until the horse lies down, as usually occurs with moderate 

 frequency in these cases on account of the animal's pain. On the 

 other hand, in cases of hernia where the bowel is distended as a 

 result of strangulation, the horse should be cast to prevent him throwing 

 himself down in the violence of his pain, but the greatest precautions 

 should then be exercised. One of the simplest methods of casting is 

 that shown in Fig. 43. It is especially useful for young animals or 

 those difficult to approach, in which ordinary hobbles cannot be used. 

 It is also useful where the hind legs have to be drawn downwards on 

 either side of the body for operations in the dorsal position, inasmuch 



