APPENDIX D 317 



therefore decided to take the unit of age as eight days, and to group 

 together all the weights of the babies from 1-8, 9-16 days of age and so 

 on up to 368 days of age. 



The total weights of all the babies which were weighed in each eight- 

 day period of life were divided by the total number of babies weighed. 

 Thus the average weight of all the babies of each series for consecutive 

 periods of eight days of life up to one year of age was obtained, the in- 

 equalities of the averages for each day being thus smoothed out and 

 the number of average weights reduced to a convenient number for 

 plotting on a curve. 



No serious overlapping of weighings was produced by this method, 

 since the babies were usually brought up at intervals of eight or ten 

 days, so that it was only in exceptional cases that the weight of the 

 same baby was recorded twice in any period of eight days. 



Appended are subsidiary tables and curves which deal more fully 

 with the material used and which may be regarded as supplementary 

 to the information given in Chap. XI. 



Table I shows the results obtained by thus working up the 

 babies of the control or breast-fed series, and Table II the corre- 

 sponding results for the babies of the boiled cows' milk series. 

 In these tables 



Column I. shows the age in periods of eight days of the babies 



considered. 



Column II. gives the number of observations, i.e. the number 

 of babies which were weighed upon each of the consecu- 

 tive days of each period of eight days ; the figures being 

 given in chronological order. 

 Column III. gives the total number of observations (weighings) 



in each period of eight days, as given in Column I. 

 Column IV. gives the average weight of the babies of each 

 series for each period of eight days corresponding to the 

 period of Column I. 



NOTE. As regards Column II., in collecting the weights of 

 the babies the weights were worked up for each day 

 separately up to 100 days of age, from 100-224 davs of 

 age they were worked up in two-day periods, and from 

 224-368 days the weights were worked up in four-day 

 periods. This is shown in the tables. 



The average weights found, and shown in Tables I and II, are 

 plotted on Diagrams, p. 196. 



The total number of observations worked up for the cases in Series I. 

 amount to 6297 an ^ f r Series II. to 5444. 



The percentage rate of growth of babies of both series. It seemed 

 desirable to study the rate of growth of the babies of the two series 

 dealt with in this report. 



This was done in the following ways : 



(1) By estimating the percentage increase per kilo, of body- 



weight during each period of eight days, each series 

 being taken separately. 



(2) The rate at which growth took place as measured by the time 



required by the babies of each series for the doubling 

 of the initial average weight, the values of the first 

 eight-day period being omitted on account of the small 



