158 Roaring in Horses. 



and spongy externally, and form rapidly, tben it may be 

 surmised they are in this condition in the larynx. 



In order to examine the interior of the larynx— which 

 may be done in about a week after the operation— it is 

 safest and most satisfactory to put the horse in the dorsi- 

 cumbent position, as for the operation, though anaesthesia 

 is not necessary. 



The electric lamp will prove useful in illuminating every 

 part, and the retractors are needed to give sufficient space 

 for scrutiny. A solid retractor (Fig. 21) does not injure the 

 external wound so much as the open one. 



Fig. 21. 



Granulations, if too luxuriant, may be cleaned from 

 mucus or pus by the small sponges with handles, and 

 swabbed with a solution of chloride of zinc (1 to 10), sul- 

 phate of zinc (1 to 60, or 2 grains to the ounce of water), 

 or corrosive sublimate solution (1 to 1,000) ; or touched 

 with solid nitrate of silver, securely held in a caustic- 

 holder with a long handle. In some cases there is no 

 need for this interference with the healing process, which 

 goes on favourably from beginning to end. In other 

 cases 'this dressing may be necessary more than once, and 

 may be repeated in the way indicated above ; while in some 

 instances tumours will appear, seemingly in spite of all pre- 

 cautions : though it must be admitted that, if the operation 

 is not well performed, and small pieces of cartilage, or shreds 

 of mucous or muscular tissue are left, they are likely to 

 spring from these. If they are discovered on examination 

 of the intra-laryngeal wound in a week after the operation, 

 they should be removed by means of scissors or the 



