PULSE RATE AND RESPIRATION BATE. 95 



PULSE RATE AND RESPIRATION RATE. 



The striking relationship existing betwen pulse rate and general metab- 

 olism, noted in the fasting experiments made with the earlier apparatus, 

 has impressed upon us the desirability of obtaining records of the pulse 

 rate as frequently as possible during an experiment. Records of the res- 

 piration rate also have an interest, though not of as great importance. In 

 order to obtain the pulse rate, we attach a Bowles stethoscope over the 

 apex beat of the heart and hold it in place with a light canvas harness. 

 Through a long transmission-tube passing through an air-tight closure in 

 the walls of the calorimeter it is possible to count the beats of the heart 

 without difficulty. The respiration rate is determined by attaching a Fitz 

 pneumograph about the trunk, midway between the nipples and the umbili- 

 cus. The excursions of the tambour pointer as recorded on the smoked 

 paper of the kymograph give a true picture of the respiration rate. 



Of still more importance, however, is the fact that the expansion and 

 contraction of the pneumograph afford an excellent means for noting the 

 minor muscular activity of a subject, otherwise considered at complete rest. 

 The slightest movement of the arm or the contraction or relaxation of any 

 of the muscles of the body-trunk results in a movement of the tambour 

 quite distinct from the respiratory movements of the thorax or abdomen. 

 These movements form a very true picture of the muscular movements of 

 the subject, and these graphic records have been of very great value in 

 interpreting the results of many of the experiments. 



