NORMAL PKOCESSES OF ENERGY METABOLISM 639 



ing the lower temperatures employed. A careful scrutiny of the several 

 tables has failed to reveal any relationship between external temperature 

 and the metabolism recorded. Doubtless the infants in the several series 

 of observations were wrapped in different quantities of clothing and bed- 

 ding necessary to maintain an environmental temperature high enough 

 to induce quiet sleep which was always the aim. Since the notes with 

 reference to this precaution are not very complete, it will be necessary 

 to give special attention to clothing before any final judgment as to the 

 influence of external temperature can bo rendered. 



In conclusion of this discussion of the factors which may influence 

 heat production in the newborn, emphasis should be placed once more upon 

 the fact attested by several observers that crying is the only normal form 

 of activity which can materially raise the metabolism above the basal level. 

 In the words of our Danish colleague, "as regards the amount of the 

 metabolism, ... it seems impossible for me to conclude anything else 

 from the tables than that the activity of the infant is the chief determining 

 factor." Hasselbalch goes on to say that even the influence of age has not 

 been demonstrated (in the newborn). While sanction cannot be given 

 to this statement since the publication of Benedict and Talbot's results 

 (see page 635), emphatic assent can be given to his estimate of the mus- 

 cular factor. The newborn does not shiver. He responds, however, to a 

 drop in external temperature, as he does to hunger, very promptly, by cry- 

 ing, and since this form of exercise is almost his only resort, it serves at 

 once the double purpose of restoring the heat production to an equality 

 with heat loss and of calling the attention of his nurse to his unhappy 

 plight. The importance of conserving the energy resources of the new- 

 born infant by keeping him warm, especially before his natural food is 

 forthcoming, is obvious. 



7. Total Energy Requirement of the Newborn. Thus far we have 

 considered the basal metabolism i. e., the metabolism of the sleeping 

 infant and have learned that body weight is nearly, if not quite, as 

 good a measure as body surface, and that length of body (stature) com- 

 bined with surface (or weight) gives possibly the best measure now avail- 

 able. The newborn up to one week of age requires for maintenance while 

 asleep 1.87 calories per kilogram and hour or about 25 calories per 

 square meter of body surface (Mech). On the 24 hour basis this becomes 

 45 calories per kilogram or 600 calories per square meter of body surface. 



The formula of Benedict and Talbot(6)(L X 12.65 X 10.3 f(w) 3 ), i. e., 

 length in centimeters times a constant times the body surface, as given by 

 Lissauer's formula, is a slightly closer approximation to the average needs. 

 There is a normal variation from this standard of 6 per cent, due to fac- 

 tors (possibly endocrine index) not yet understood. 



For the time during which the infant is awake and crying, the require- 

 ment, as nearly as it can be estimated to-day, is from 30 to 40 per cent 



