DISCUSSION OF RESULTS. 107 



"The pulse is a little more frequent in females than in males. Muscular 

 exercise or excessive excitement increases the pulse-rate from 20 to 50 beats. 

 Very trivial causes disturb not only the frequency but the force of the pulse." 



Some figures are given in a few observations by Townsend, 1 which 

 show that the pulse-rate of the crying baby is more rapid than that 

 of the quiet baby, but no definite, continuous data have been reported 

 other than the observations published by the writers in a previous paper. 2 



An examination of the records thus far given in this report shows 

 that it is of the greatest moment whether the infant is asleep or awake 

 when the pulse observations are taken. It is probable that most of the 

 records of pulse-rate previously reported by observers have been made 

 when the infants were awake and possibly more or less restless. But 

 little data are available, therefore, as to the minimum pulse-rate and the 

 length of time required for the pulse to reach the minimum after muscu- 

 lar activity. 



PRELIMINARY OBSERVATIONS. 



To secure more definite information on this subject, observations 

 were made by one of us (F. B. T.) at the Boston Lying-in Hospital 

 and the Directory for Wet Nurses at the Massachusetts Babies' Hospital, 

 in which a stethoscope was attached directly to the infant. Records 

 could thus be taken by skilled nurses without disturbing the subject. 

 From this extended series, a few typical pulse curves have been selected 

 for reproduction here, including two previously published in the paper 

 referred to. These give a fair index of the fluctuations which would 

 normally be expected with infants of different ages and varying activity. 



The curve shown in figure 11 was obtained with S — ns at the age 

 of 3 days, the records being taken practically every 5 minutes between 

 7 h 5 m p. m. and 6 h 28 m a. m. The maximum pulse-rate was 161 beats 

 and the lowest observed value was 101 beats. When the curve is 

 carefully examined, it will be seen that there was a general tendency 

 for the pulse-rate to fall to a minimum of not far from 112 to 115, 

 although the line is characterized by rapidly varying fluctuations. 



The second curve (see figure 12) was obtained 5 days later with the 

 same infant, and shows the general irregularities of the first. The 

 maximum record is even higher, i. e., 174, while the minimum is 108. 

 During the latter part of the night, the minimum count was not far 

 from 115 beats for several minutes. 



A similar set of observations was made with Dow, 4 days old, cover- 

 ing the same period of time as those with the first infant (see figure 13). 

 The maximum pulse-rate with this infant was 165 and the minimum 



iRotch, Pediatrics, 5th ed., 1907, Philadelphia and London, p. 67. 



2 Benedict and Talbot, Am. Journ. Diseases of Children, 1912, 4, p. 129. Since this was written 

 the valuable article by Katzenberger, Zeitschr. f. Kinderheilk., 1913, 9, p. 167, entitled Puis und 

 Blutdruck bei gesunden Kindern, has appeared. 



