202 OPEBATIONS ON THE SKIN AND CELLULAR TISSUE. 



while it is necessary to preserve the skin which covers it. What- 

 ever form of uioision may be used, it must always extend beyond 

 the base of the tumor to allow a free dissection and an easy removal 

 of all the diseased tissues. The convex bistoury is preferred in 

 this step of an operation and must be apphed with light pressure, 

 and a very guarded motion, to avoid any subcutaneous blood ves- 

 sels that may run over the surface of the growth, and which may 

 ,be of large size. 



The incision is followed by the dissection, which is done with 

 the scalpel or the bistoury, by separating the tumor from the teg- 

 uments, carefully avoiding surrounding structures, which should 

 be held aside with the forceps or tenaculum, in order to keep 

 the wound open and accessible. Instead of the scalpel or bis- 

 toury, the blunt end of the scissors sometimes becomes the in- 

 strument by which the adhesions of the cellular tissue covering 

 the tumor are most easily destroyed. 



In the third step, or the extirpation of the tumor, either the 

 bistoury, the scalpel or the sage knife may be the most eligible in- 

 strument, according to the consistency of the tumor, whether hard, 

 cartUagiaous or bony If it is of sufficiently small size, by steady- 

 ing it vrith the forceps or tenaculum, it may be excised with a 

 single stroke of the instrument. If too large for this, it may be 

 controlled by passing a loop of ribbon or tape through it, by which 

 its position can be changed at pleasure, to facilitate its complete 

 dissection. The hemorrhage following may be arrested by any of 

 the usual hemostatic measures. When the tumor is of large di- 

 mensions this last step of the operation wUl require great care in 

 the execution, and the blood vessels which may run through its 

 base must be securely ligated before the tumor is entirely excised. 



Fig. 225.— Eoraseur of Chaaaalgnac. 



