ELEMENTARY EXPERIMENTAL PHYSIOLOGY 



141 



tambour. The writing styles of the manometer float and of the tambour 

 are brought to write on the kymograph exactly beneath one another. 



R' 



-T 



-F 



FIG. 137. Arrangement of cannula, pressure bottle, and mercurial manometer for 

 recording blood pressure. C, cannula ; p, p', clips ; F, float ; S, writing style. 



A clock marking seconds and an electric signal placed in the primary 

 circuit are also brought to write on the kymograph. The primary 

 circuit is arranged to give tetanising shocks, and shielded electrodes 



FIG. 138. Electrodes for exciting vagus and other nerves. (Sbcrriugton). 



are connected with the secondary coil by means of a Du Bois key, and 

 are placed in position under the peripheral end of the vagus nerve. 

 The clip is then removed from the carotid artery and the kymograph 

 started. Note the height of the arterial pressure, the cardiac pulsations, 



