62 GASEOUS METABOLISM OF INFANTS. 



We are far from satisfied with this as a permanent method for 

 securing a record of the pulse-rate, and it is our hope, in connection 

 with the hospital or with the laboratory, to secure records either with 

 the string galvanometer or with the Bock-Thoma oscillograph. It is 

 clear that the records of the pulse-rate should be more objective than 

 they can be even with a specially detailed assistant. During the experi- 

 mental period, it is necessary to have the room absolutely quiet, and 

 hence the assistant is not distracted by extraneous sounds. We regret, 

 however, that a better method was not at the time practicable for 

 recording a factor which is of such great significance in determining 

 the general tonus of the body and therefore the basal metabolism. 



GENERAL TECHNIQUE OF RESPIRATION EXPERIMENTS WITH INFANTS. 



Previous to an observation, the length of the baby was measured by 

 placing it upon a board with a head-board at right angles and a sliding 

 foot-board. Subsequent to May 1, 1913, the infant was measured 

 while flat on his back. Measurements were likewise taken of the cir- 

 cumference of the head above the ears, the chest oyer the nipples, and 

 the abdomen over the umbilicus, as well as the greatest circumference 

 of the thighs and the calves. The baby was also weighed naked. The 

 rectal temperature was taken and recorded and the baby was given 

 its food, except in certain instances when boiled water sweetened with 

 saccharine was substituted. The infant was then immediately taken 

 to the room in which the respiration chamber was placed. 



Preliminary to the respiration experiment, the kymograph was 

 wound, the wet bulb of the psychrometer thoroughly moistened with 

 distilled water, the tambour tested under water to make sure that 

 there was no defect in the rubber, and the pneumograph likewise 

 tested for tightness. A sensitivity test of the apparatus was then 

 made as previously described. In the bottom of the crib a small 

 mattress or folded blanket was laid. The stethoscope was next prop- 

 erly adjusted by means of small strips of adhesive plaster and as soon 

 as the infant was placed in the crib, the stethoscope tube was connected 

 with the copper pipe in the wall leading to the earpieces outside. If 

 the crib did not swing freely, the tension of the spring could readily 

 be adjusted by raising or lowering a screw. In most instances, after 

 placing the infant in the crib, it was found advantageous to pin the 

 blanket in which it was wrapped at both the top and the bottom in 

 the same manner that infants are wrapped when they are put to bed. 

 The cover of the apparatus was then put on, the thermometer inserted 

 in the top, the window covered with a black cloth, the ventilating 

 current set in motion, and the time recorded. 



The usual preliminary period sometimes lasted a considerable length 

 of time, for it is obviously unwise to begin the first period of observation 

 until the infant has been quiet for at least 15 minutes. The tempera- 



