

UNIVERSITY 



' 

 THE CIRCULATION OF THE BLOOD ' 91 



To trace the carotid pulse, place the open mouth of the receiving 

 tambour, over which no membrane has been stretched, over the 

 course of the carotid artery beside the larynx, taking care that 

 the side vent of the pressure tube is open while the adjustment 

 is being made. Close the vent, and if the adjustment has been 

 successful the lever will show the carotid pulse. Trace it upon the 

 kymograph. 



Compare the carotid sphygmogram with the radial sphygmogram. 

 Account, if possible, for any essential difference. 



One may trace a radial sphygmogram with the same instrument 

 by stretching a rubber membrane rather tightly across the mouth of 

 the receiving tambour cementing a bone collar-button to the middle 

 of the membrane then placing the head of the collar-button upon 

 the radial artery. 



VII. TO DETERMINE THE ARTERIAL BLOOD PRESSURE IN AN 



ANIMAL. 



1. Appliances. Dog or a large rabbit; mercurial manometer, 

 with manometer tambour. (See Appendix, 13.) In lieu of the 

 manometer tambour (Fig. 52) one may use the ivory float with 

 tracing point in the distal limb of the manometer; kymograph; 

 chronograph; physiological operating case; glass arterial cannulse; 

 half-saturated solution of sodium carbonate, sodium sulphate, or 

 magnesium sulphate ; clippers; dog board or rabbit holder; absorb- 

 ent cotton; one-half grain of sulphate of morphine; hypodermic 

 syringe; chloroform and ether. 



2. Preparation. The manometer should be filled with mercury 

 with at least 10 cm. in each limb. Attach to the proximal limb 

 of the manometer a piece of pressure tubing 6 or 8 inches in length, 

 to which attach one limb of a T-tube. To the opposite limb of the 

 T-tube attach another piece of pressure tubing not less than a foot 

 in length, into the end of which the glass cannula can be placed. 

 To the side limb of the T-tube attach a rubber tube, which may be 

 carried upward to an inverted flask filled with the non-coagulant 

 (Na a CO 3 , Na 2 SO 4 or MgSO 4 ). The tube leading from the reservoir 

 should have a screw clamp near the T-tube. The reservoir may 

 be supported near the top of the same stand which supports the 

 manometer. 



If a dog is used for the experiment he should be given from J to 

 J grain of morphine twenty minutes before the anaesthesia with 

 chloroform. If a large rabbit is used anaesthetize with ether. 



3. Operation. After fastening the animal to the holder, clip the 

 throat, make an incision from the upper end of the sternum over 

 the right sternothyroid muscle to the middle of the neck, cutting 



