707 
Like most fundamental investigations, his line of procedure was 
quite simple, being merely to determine the daily amounts nursing 
children took at the breast, each day for successive months, to tabulate 
the daily and weekly gains observed, and finally to determine by 
chemical analysis the composition, and from that the calorific energy 
of the milk that produced it. 
His results show that, on the average, nursing infants, in order to 
thrive, require the following food value, or energy’ quotient as he 
calls it, per kilogram of body weight : First week in life, 60 calories® 
per kilogram of body weight; first three months, 100 calories per 
kilogram of body weight ; second three months, 100 to 90 calories per 
kilogtam of body weight ; third and fourth three months, 80 calories 
per kilogram of body weight. 
His results were confirmed by Feer, Xordheim, Beutner, Czerny, 
Keller, and others. He also found that an energy’ quotient of 70 was 
the minimum on which a child of less than 1 year of age could 
maintain its weight. An}" diminution of the quotient below this 
level was followed. by a loss. Moreover, the researches of Czerny and 
Keller^ have shown that the energy quotient of 100 calories per 
kilo of body weight marks an upper limit which can only be tem- 
porarily surpassed without inducing disastrous nutritive and gastro- 
intestinal disturbances. These disturbances will be later discussed 
under the head of overfeeding.*’ 
A necessary part of these researches was the determination of the 
caloric value of mother’s milk. As human milk varies in composi- 
tion, not only in different individuals but at different stages of its 
secretion from the breast, only average values could be found. Ac- 
cording to the richness of the milk, it varied from 61-1.2 to 723.9 when 
lactation was fairly established with an average caloric value of 650 
to the kilogram. 
The determination of the caloric value of any food substance is 
very easy once we know its percentage composition as one gram of fat 
produces 9.3 calories and one gram of proteid, and one gram of car- 
bohydrate have each a caloric value of 1.1. 
Thanks to these investigations we are now in a position to deter- 
mine most exactly, if desired, the amount of food required by each 
individual child in order to nourish it and give it growth and have, 
furthermore, data by which we determine whether it is getting too 
much, in time to avert the disastrous consequences. 
a This term, as used in this paper, refers to large calories, or the amount of 
heat requisite to raise 1 kilogram of water 1° C. in temperature. 
6 Czerny and Keller, Des Kindes Erniihrung, Ernahrungsstorungen und 
Ernahrungstherapie. 
