MEASUREMENT OF THE TIME OF THE RESPIRATORY MOVEMENTS. 231 



movements upon a revolving cylinder. Every dilatation of the chest compresses 

 the membrane, and thus the air within the tambour is also compressed. 



(3.) A cammla or O3sophageal sound may be introduced into that portion of the 

 oesophagus which lies in the chest, and a connection established with an Upham's 

 capsule p. 132 (Rosenthal). 



Marey's Stethograph or Pneumograph. [There are two forms of this instru- 

 ment, one modified by P. Bert and the more modern form (Fig. 102). A tambour (h) 

 is fixed at right angles to a thin elastic plate of steel (/). The aluminium disc on 

 the caoutchouc of the tambour is attached to an upright (b), whose end lies in con- 

 tact with a horizontal screw (g). Two arms (d, c) are attached to opposite sides of 

 the steel plate, and to them the belt (e) which fastens the instrument to the chest 

 is attached. When the chest expands these two arms are pulled asunder, the steel 

 plate is bent and the tambour is affected, and any movement of the tambour is 

 transmitted to a registering tambour by the air in the tube (a).] 



In the case of animals placed on their backs, Snellen introduced a long needle 

 vertically through the abdominal walls into the liver. Rosenthal opened the 

 abdomen and applied a lever to the under surface of the diaphragm, and thus regis- 

 tered its movements (PHRENOGKAPH). 



Fig. 104. 



Pneumatogram obtained by means of Riegel's Stethograph I, normal curves; II, 

 curve from a case of emphysema; a, ascending limb; b, apex; c, descending 

 limb of the curve. The small elevations are due to the cardiac impulse. 



The curve (Fig. 103, B) was obtained by placing the tambour of a 

 Brondgeest's pansphygmograph upon the xiphoid process, and recording 



