XXIX. The action of the diaphragm. 



1. Appliances. Operating case; clippers ; rabbit board, or 

 dog board ; rabbit or dog ; ether ; ether cone ; absorbent 

 cotton ; kymograph ; chronograph ; recording tambour; 

 beaker with warm water; medicine dropper or bulb. (If 

 a dog be used, the medicine dropper will not be large 

 enough, its place may be taken by a soft spherical rub- 

 ber bulb about 2 cm. in diameter.) Inductorium, 1 cell, 

 2 keys, vagus electrode, 5 common wires and 2 fine 

 wires. Sometimes the bulbs mentioned above, and usu- 

 ually used for this purpose, are not satisfactory. Very 

 good results may be gotten by using a piece of glass rod, 

 which has been rounded at one end and sharpened at 

 the other, as a lever. (Fig. 21.) The rounded end is 

 passed through the abdominal wall and rests against the 

 diaphragm, (</). The point is inserted into the cork 

 button of a tambour. Any contraction of the dia- 

 phragm presses the round end down, the body wall 

 serves as a fulcrum (/), the point is pressed up and the 

 lever of the recording tambour rises. 



2. Preparation. Fix the animal to the board; anaesthetize; 

 clip anterior median region of abdomen. Put the bulb 

 into the warm water, join the glass tube of the bulb to the 

 recording tambour through a rubber tube. This appa- 

 ratus thus joined may be called a phrenograph and its 

 record a phrenogram. 



Set up electrical apparatus with short-circuiting key 

 in secondary coil. 



j. Operation. From the posterior extremity of the 

 xyphoid appendix make a median incision through the 



132 



