202 OPERATIONS ON THE SKIN AND CELLULAR TISSUE. 



while it is necessary to preserve the skin which covers it. "^Tiat- 

 ever form of incision 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 applied 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 scaljiel 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 eUgible in- 

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

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

 ing it with 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 com^Dlete 

 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 will require great care in 

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

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



Fig. 226.— Ecraseur of Chassaignac. 



