CYSTIC TUMOURS. 439 



Wlien on the elbow, the best treatment is the reduction of 

 tlie tumour by puncture ; the cavity afterwards injected with a 

 solution of sulphate of zinc, or of iodine, and the orifice of 

 puncture kept open until the cavity of the cyst has become 

 obliterated. Another plan is to excite the suppurative action 

 in it after it has been punctured, by injecting a stimulating 

 mixture, as ammonia and oil, or by inserting a seton through 

 its centre. It is useless to puncture and allow the wound to 

 close immediately, for the Avails of the sac have acquired 

 secreting properties, and continue to pour out the serosity, which 

 will speedily fill the cavity of the cyst. It is therefore necessary 

 to keep the puncture open until the walls of the sac have be- 

 come adherent to each other, and its cavity destroyed. 



When the cyst has become consolidated by the causes already 

 given, it will often be found that a little suppuration occurs in 

 the centre of the tumour ; but it is never very extensive, and 

 the suppurative spot is surrounded by a thick wall of condensed 

 fibrous tissue of a greyish appearance. 



There are two ways of removing the tumour when in this 

 condition — by excision, and by sloughing it with escharotics. 

 I have tried both plans, and prefer the latter, provided it is 

 carefully done. I puncture the tumour in two or three places, 

 and insert into each puncture a very small quantity of finely 

 powdered corrosive sublimate and arsenic, in equal parts, rolled 

 up in a small piece of tissue paper. The effect of this is two- 

 fold: — (1st.) It destroys the vitality of the tissue which it 

 touches; and (2d.) Excites absorption throughout the whole 

 extent of the tumour. The absorption first excited in the living 

 structures in immediate contact with those destroyed by the 

 agent, whereby a line of demarcation is formed between the 

 living and dead tissue, becomes general throughout the tumour, 

 and in a few days it will be seen that it has diminished in 

 volume in every direction. After the sloughs caused by the 

 escharotics have been removed, the parts should be kept clean 

 for a few days, at the end of which it may be necessary to reapply 

 the caustic. 



If excision with the knife be preferred, the operator must 

 make his incision in the perpendicular direction only, as a 

 crucial incision leaves an ugly blemish. Two incisions parallel 

 to each other may be required in very large tumours, and about 



