PRELIMINARY OPERATIONS 



315 



ficulty of manipulating so many pieces in the chest at one 

 time. The beating of the heart greatly increases the dif- 

 ficulties of the operation. The artery has thin walls and a 

 sharp-edged or strong-springed bull-dog will sometimes 

 quickly wear a hole in the vessel from the constant rubbing 



To manometer 



Fig. 278. 



-For washout 



Fig. 279. 



Fig. 278. Special form of separable pointed cannula for the pulmonary artery. 



Fig. 279. Special (all-glass) form of cannula for the pulmonary artery. The open- 

 ing m the point should be about one-eighth inch in diameter (the pulmonary artery is 

 large). 



