248 EXPERIMENTAL PHYSIOLOGY. 



a broad band placed round the neck, the horizontal bar being 

 behind the body. 



(b.) The most important diameters of the chest to measure 

 are" Those connecting the eighth rib in the axillary line 

 with the same rib on the opposite side, the manubrium 

 sterni .with the third dorsal spine, the lower end of the 

 sternum with the eighth dorsal spine, and the ensiform 



Fig. 114. Marey's Stethograph. 



cartilage with the tenth dorsal spine." Measure only the 

 first. Adjust the knob of the tambour on one side against 

 the eighth rib, as above, while the movable bar with its 

 knob is placed against the opposite corresponding rib. Con- 

 nect the tambour with the recording tambour, introducing 

 a T-piece, the stem of which is provided with an india- 

 rubber bag and screw clamp to regulate the pressure within 

 the air-system. 



3. Intra-Thoracic Pressure. For practice this can be done on 

 a dead rabbit. 



(a.) Fix the dead rabbit in Czermak's rabbit-holder. 

 Expose the trachea, tie into it a knee-shaped glass cannula. 

 Make a small water-manometer or bent U-tube, with a 



