THE OPERATION. 121 



space between the first and second ribs ; 

 with the left-hand thumb and finger draw 

 the skin tense, ascertaining positively the 

 space between the ribs. Then, with the 

 knife in the right hand, make a single cut 

 through the skin only, about an inch long, 

 measuring from the point of the first rib 

 backward. This exposes the two ribs and 

 the margin of a large muscle running down 

 the thigh. This muscle is in no danger of 

 being injured if the proper point is ascer- 

 tained where to make the incision ; but if 

 otherwise, an injury to it will cause lame- 

 ness. Divide the muscle between the ribs 

 by introducing the knife at the point of the 

 first rib, and cutting backward about an 

 inch. In this way the pleura is avoided, 

 and, of course, an escape of air. 



Introduce the hooks, which will, by the 

 power of the reed, draw apart the ribs, and 

 expose a bundle of muscular fibres, called 

 the internal costal muscle. Should the in- 

 cision be too small, it may be enlarged by 

 passing the knife round the point of the sec- 

 ond rib ; this v :n divide the ligamentous 

 K 



