16 PHYSIOLOGY OF THE NEW-BORN INFANT. 



RESPIRATION EXPERIMENTS WITH NEW-BORN INFANTS. 

 BY K. A. HASSELBALCH. 



The desirability of carrying out total metabolism experiments on 

 healthy and sick infants with a view to obtaining information regarding 

 the adequate nourishment of the infant is very evident. So long as it 

 is not an established fact how the healthy and normally-nourished infant 

 utilizes the fat and carbohydrate of milk, so long every therapeutic treat- 

 ment of the fatal conditions in pedatrophia is absolutely guesswork, and 

 so long the composition of the countless strength-giving foods for 

 artificially nourishing infants is based on the roughest empiricism by 

 observing the changes, if any, in the curve of the body-weight. 



While the present paper does not report experiments on total metabo- 

 lism, a study of the respiratory exchange of the new-born infant is also 

 of considerable interest. In the first place, the amount of the respira- 

 tory exchange, because of its considerable excess over the nitrogen 

 exchange, may be used as an expression of the amount of the total 

 metabolism, and in the second place the respiratory quotient throws 

 light on the substances oxidized in a given period of time. 



It is generally believed that a young individual has a greater metabo- 

 lism per kilogram of body-weight than the adult, because of its greater 

 surface in relation to its body-weight and because it is growing. I shall 

 not enter into a discussion of the rather contestable "law of surface 

 area" which is the subject of so much dispute. My experiments 

 can not be used to support such a discussion successfully, for it is 

 rather difficult with young children to represent fairly the same external 

 and internal experimental conditions as are represented by other inves- 

 tigators in their respiration experiments with adults. In one respect 

 only can my experiments give enlightenment, that is, as to the influence 

 of exercise on the amount of the metabolism. From experiments 

 during which the infant slept quietly I have obtained material whereby 

 I could form my own point of view in regard to the dogma concerning 

 the relatively large metabolism of the infant. If it is possible from the 

 experiments to come to an approximate conclusion concerning the 

 amount of the metabolism of the new-born sleeping infant, this conclu- 

 sion has a special interest as bearing directly on the fetal life. In the 

 embryonic condition it is well known that the metabolism per unit of 

 body- weight is as great as with the grown individual of the same species. 



The respiratory quotient, obtained as soon as possible after birth, 

 gives information as to the approximate composition of the new-born 

 infant's fuel material and permits an assumption as to its composition 

 in the embryonic state. The breast-fed infant and the infant that 

 directly after birth has been given the spoonful of cane-sugar solution 

 traditional in Denmark 1 give the experimenter some idea of the time 



1 The following information regarding this practice is kindly supplied by Hasselbalch in a 

 personal communication: "The midwife gives the child a teaspoonful or two of a weak cane-sugar 

 solution (strength of solution quite accidental) after the child is washed and before it is put to bed. 

 We suppose the reason to be that the child should not be starving until the mother has milk enough 

 for it. Generally the administration of cane-sugar is not repeated, as the role of the midwife is 

 now over and the nurse's work begins." 



