PERFUSION OF HEART 



75 



If the tube g is vertical instead of horizontal the apparatus can be 

 \ 'mployed with a vertical drum, but the piston must fit very accurately. 



It may happen that the perfused heart (which is a Stanniused 

 heart) does not begin to beat spontaneously, although the salts and 



s 



U 



.2 05 



Jl 



II 

 ' * 

 a < 



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g>g 



the pressure of fluid serve as a slight stimulus. In that event the 

 beats may be started by faradic excitation from an induction coil, one 

 electrode being attached to the metal cannula and the other to a wire 

 which passes up through a cork in the bottom of the plethysmograph, 

 and is brought in contact with the ventricle. 



