8 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



conditions. He pointed out that this is likewise true even during 

 sleep, when the metabolism is lower, for Lewin's adult subject 1 gave 

 off in sleep 3.5 grams of carbon dioxide per 10 kg. of body-weight per 

 hour, while Forster's sleeping infant gave off 9 grams of carbon dioxide. 



Speck, 1889. Speck's observations on children really antedated the 

 work of Forster, for, although his results were not published until 

 1889, 2 experiments on a 13-year-old girl, weighing 35 kg., were begun 

 on September 2, 1871, and continued at intervals for two or three 

 weeks. Speck points out that this child used less oxygen than a 

 normal man, but when the results were computed on the basis of 

 oxygen consumption per kilogram of body-weight the metabolism of 

 the child appeared to be more intensive than that of the adult. All 

 the experiments with this subject were made in the standing position 

 and without food. Beginning September 5, 1877, six experiments in 

 about two weeks were made with a 13-year-old boy, weighing 38 kg. 

 During these observations the boy was without food and sat reading 

 quietly. Both the total carbon-dioxide production and the oxygen 

 consumption were less than with the average man, but much higher 

 when computed on the basis of body-weight. Thus the total oxygen 

 consumption was 239 c. c. per minute and 6.3 c. c. per kilogram of 

 body-weight; the respiratory quotient was 0.824. Still another 

 series of experiments was made by Speck August 22 to 29, 1881, the 

 subject being a 10-year-old girl, weighing 25.4 kg. This girl, when 

 studied 5 hours after breakfast and while she was sitting quietly 

 reading, gave low values as compared to those obtained with a man, 

 but on the basis of body-weight the results were much higher. The 

 average total oxygen consumption was 172 c. c. per minute and 6.9 c. c. 

 per kilogram of body- weight per minute; the respiratory quotient 

 was 0.855. Since a normal man gave about 4 c. c. of oxygen per 

 kilogram of body-weight per minute, he concluded that a small body 

 absorbs relatively more oxygen than a larger one and that during the 

 years of growth the oxygen absorption is greater than with adults; 

 furthermore, that under like conditions males have a greater metab- 

 olism than females. 



As Speck's experiments were made with the subject sitting (and in 

 one instance standing) instead of with the subject lying, and in a 

 number of instances with food in the stomach, the results are not 

 strictly comparable with those of modern work. It is, however, sig- 

 nificant that Speck's conclusions, based upon these physiological 

 observations with persons of various ages, and particularly with him- 

 self, have been unaltered by the results obtained by most modern 

 writers. His conclusions regarding metabolism during youth are in 

 accord with most subsequent work. 



J Lewin, Zeitschr. f. Biol., 1881, 17, p. 71. 



2 Speck, Physiologie des menschlichen Athmens, Leipsic, 1892, p. iv 



