210 



EXPERIMENTAL PHARMACOLOGY 



record.) The animal should be firmly tied down to the 

 operating board so the chest cannot move too much. 



Now pass ligatures through the sides of the neck as dp- 

 scribed in Experiment XXIX, page 195 (see also Experi- 

 ment XXVIII, 2, page 192 and Figs. 183 and 184). Isolate 

 the left carotid artery and arrange to inject chloroform 

 (one or two cubic centimeters) into it. Proceed as in Ex- 

 periment XXIX to destroy the animal's brain, but try to 



Glass tube 



;7b recording tambour 



Hemostat clamping string 

 on corK to cftesr, 



Adjustable c/a/np 

 (by-pass)' 



Fig. 201. Arrangement of apparatus for recording the volume changes of the right 

 lung by use of the lung shield. The glass tube shown in the upper part of the illustra- 

 tion has its bent end passed into the chest cavity. 



do this by injecting the chloroform into the left carotid 

 artery alone. If you succeed well in this you can avoid 

 dissecting out the right vertebral artery. The blood-pres- 

 sure should come down at least to a height of one or one 

 and one-half inches above the base line as seen on the drum. 

 If the pressure does not fall, or even goes up higher, the 

 injection has not succeeded. A very high pressure thus 



