148 



OPERATIVE TECHNIQUE. 



the sabre-shaped or abscess lancet, ha\-in,i; one convex and one concave 

 cutting edge. 



To bleed with the lancet, though apparently easy, requires con- 

 siderable practice ; the \arying thickness and resistance of the skin in 

 different animals making it difficult to judge of the exact amount of 

 pressure required to open the vein without transfixing it. 



For this reason other instruments have come into use. The 

 simplest of these is the fleam (Fig. 173). The handle extends some- 



FlG. 17^. 



F"iG. 173. — Simple 

 fleam. 



Im ,, 171). — L'asc of fleams. 



Fig. 177. — - 

 Blood-stick. 



\vhat beyond the insertion of the actual cutting part, and is intended 

 to prevent the instrument entering too deeply. Sometimes the back of 

 the handle is provided with a broad surface (Figs. 174 and 175) on which 

 the blow of the blood-stick is delivered. Combined fleams having a 

 number of blades in one setting are also common (Fig. 176). The 

 fleam is caused to penetrate the vein bv a sharp blow from the' hand 

 or blood-stick (Fig. 177). With the latter the necessary force can 

 better be estimated, and the inconvenience of either failing to 

 penetrate the vessel or completely transfixing it equally avoided ; in 



