APPARATUS AND METHODS USED IN THIS RESEARCH. 61 



As yet no attempt has been made to measure the amount of increase 

 in metabolism incidental to one complete revolution of the wheel, and 

 it is a question whether quantitative values can be obtained with this 

 device, especially for the comparison of results with different infants. 

 But this method, which is inexpensive and simple, gives a general 

 index of the degree of restlessness or muscular repose of infants, which 

 should prove of value for ward use. This has already been shown in 

 our more recent observations. 



J.R 

 NOV. 14- - NOV. 15.1913 



V. 17- NOV. 16. 1913 I 



NOV. 17 - NOV. 16. 1913 



Fig. 9. Typical kymograph curves obtained with the ward crib recorder. 

 METHOD OF RECORDING THE PULSE-RATE. 



Previous experiments with adults in the Nutrition Laboratory, in 

 which the large respiration chambers were used, showed a striking 

 relationship between the pulse-rate and the metabolism. Attempts 

 were accordingly made to secure accurate pulse records in our observa- 

 tions with infants. For this purpose we attached the bell of a small 

 Bowles stethoscope to the infant over the apex beat of the heart by 

 means of strips of adhesive plaster. A rubber tube connecting with 

 the bell led to a pipe in the wall of the chamber, a piece of rubber tubing 

 and the earpieces being attached to the outer end of the tube. Even 

 with a total length of some 2 or 3 meters from the bell to the earpieces, 

 it was possible to count the pulse-rate of the weakest infant. 



Since here again there is a direct connection between the inside of 

 the chamber and the outside air, it is of the highest importance that the 

 stethoscope and the rubber tube leading from it be tested for tightness. 

 For this test, the stethoscope bell is immersed in water, and a slight 

 pressure is put upon the diaphragm by blowing through the rubber tube. 

 If it is not found absolutely tight, a thin coating of vaseline on the edge 

 of the diaphragm usually insures a complete closure. 



The importance of these pulse observations is so strongly impressed 

 upon us that a special assistant is at present detailed in all of the experi- 

 ments with infants for the sole purpose of recording the pulse-rate. 

 The major muscular movements of the infant and any abdominal or 

 chest sounds, such as grunting, sneezing, coughing, etc., may readily 

 be heard through the stethoscope and are likewise regularly recorded 

 upon the protocol sheet. It is also perfectly feasible to secure the 

 respiration-rate in this way from time to time. 



