12 



GASEOUS METABOLISM OF INFANTS. 



and gives protocols for another experiment, 1 hour in length, presum- 

 ably with the same infant. In summing up his averages he refers to 

 numerous experiments on infants weighing from 6 to 9 kilograms and 

 includes observations made with environmental temperatures ranging 

 from 18° C. to 25° C. He concludes that the infant produces on the 

 average 4 calories per kilogram of body-weight per hour. Richet dis- 

 cusses especially the relationship between the body-surface and the 

 heat-production. 



Two years later, Langlois 1 conducted experiments on children with 

 Richet's calorimeter, in which only the heat-production was measured. 

 From 17 controlled experiments, all with infants weighing about 7 

 kilograms, Langlois concludes that the heat-production is increased 

 as the environmental temperature is lowered. As a result of a study 

 on the influence of the time of day upon the heat-production, he also 

 concludes that there are two maximum values at approximately 1 1 a. m. 

 and 3 p. m., corresponding to the values for the absorption of oxygen 

 found by Fredericq. 2 



Table 1.— Relationship between heat-production and body-weight of infants (Langlois). 



Table 2.— Relationship between heat-production and body-surface of infants (Langlois). 



This figure is quoted from Langlois and as his discussion of body-surface is very 

 confusing, it is impossible to make a correction which is obviously much needed. 



2 As calculated by Camerer, using Meeh's formula (Camerer, Der Stoffwechsels 

 des Kindes, Tubingen, 1896, p. 109). 



Langlois's discussion of the relationships between the heat-production 

 and the body-weight and the heat-production and the body-surface is 

 of special interest in connection with our research. As will be seen 



langlois, Centralbl. f. Physiol., 1887, 1, p. 237. 2 Fredericq, Arch, de Biol., 1882, 3, p. 731. 



