130 



ELEMENTARY OPEKATIOKS. 



Pis. 160.— Sage Knife held with One Hand, 



Fig. 181.— Sage Knife held with Two Hands. 



needful, is that in some cases it is handier to grasp them from 

 above and in others from below. 



There are some general rules which are important to observe 

 in performing the simplest operation. These relate to the condi- 

 tion of the iastrument, to the preparation of the parts, and to the 

 direction and dimensions of the incision. 



The condition of the instrument must be such that the soft 

 tissues may be divided with but little pressure. It must cut and 

 not tear. Therefore, besides their state of thorough cleanliaess, 

 they must be very sharp and their edge entirely smooth and free 

 of indentation, which would cause them to act as a saw and pro- 

 duce an irregular and ragged incision, more painful to the patient, 

 and more difficult to heal. It has been recommended to dip them 

 before using in oil or warm water, but these precautions can be 

 dispensed with. 



The region upon which the incision is to be made must be 

 thoroughly cleaned, the hairs being clipped short, and sometimes 

 even shaved. In these days of antisepsy, it is proper to soak it 

 well, after it is washed, with some antiseptic solution. To make a 

 clean incision, the skin must be well stretched with the hands, the 

 instrument firmly held, and the division made by a steady move- 



