Nutrition and Other Subjects of Allied Interest 91 



the maximum working capacity of man, and particularly the after-effects of work. 

 A certain amount of evidence was available for a comparison of results obtained 

 with trained and untrained individuals. 



An extensive review of the earlier literature, with an analysis of the results 

 obtained by former investigators, is included in the report. 



No. 201. BENEDICT, FRANCIS G., and FRITZ B. TALBOT. The Gaseous Metabolism 

 of Infants with Special Reference to its Relation to Pulse-rate and 

 Muscular Activity. Octavo, 168 pages, 65 figures. Published 1914. 

 Price $1.50. 



A complete historical review of all the literature on the gaseous exchange and 

 calorimetry of infants is followed by a presentation of several important problems 

 in this field. A respiration apparatus, measuring simultaneously carbon-dioxide 

 production and oxygen consumption and provided with a sensitive arrangement for 

 registering automatically and graphically the slightest body movement, was used to 

 study 37 infants during approximately 800 periods of observation. Continuous 

 records of the pulse-rate, and a graphic representation of the degree of muscular 

 repose enabled many important correlations with the respiratory studies. Distinct 

 evidence of an increased pulse-rate and metabolism independent of external activity 

 was interpreted as being an indication of internal work and suggested the pulse-rate 

 as an index of this internal work. 



Particular stress was laid upon a comparative study of the basal metabolism of 

 the infants, i. e., the metabolism during complete muscular repose as shown by the 

 kymograph records. Under these conditions, it was found that while, in general, 

 the smaller infants had the smaller total metabolism, there was a sufficient number 

 of striking exceptions to prevent the formulation of a definite law. Similarly, there 

 was no uniformity in the metabolism per kilogram of body-weight, although with 

 "normal" children the plotted chart gave indications of an approximately regular line. 



A discussion of the supposed relationship between body-surface and metabolism 

 and a critique of the methods used for measuring body-surface introduces the dis- 

 cussion of the values found with these infants. No relationship was found between 

 the age of infants and the heat produced per square meter of body-surface, 

 nor could any relationship be noted between the heat-production per square meter 

 of body-surface and the actual body-weight, the normal weight for the age, or the 

 expected body-weight. 



Evidence secured with normal and atrophic infants of different ages and weights 

 is presented to show that the active mass of protoplasmic tissue determines the 

 heat-production. This active mass of protoplasmic tissue may be stimulated to a 

 greater or less cellular activity, the intensity of the stimulus being indicated by the 

 pulse-rate. 



No. 203. BENEDICT, FRANCIS G. A Study of Prolonged Fasting. Octavo, 416 

 pages, 5 plates, 47 figures. Published 1915. Price $4.00. 



In the spring of 1912 an experiment was made at the Nutrition Laboratory on 

 a subject, A. L., who subsisted for 31 days without food, drinking during that 

 period only 750 c.c. of distilled water per day. Observations were also made for 

 4 days prior to the fast and imperfect observations for 3 days subsequent to it. 

 The main object of the investigation was to determine simultaneously as many 

 factors in the physiology of the subject as possible. The research included physical 

 examinations by a physician, accompanied by photographic studies and careful an- 

 thropometric measurements; records of the body-weight, rectal temperature, pulse- 

 rate, and blood pressure; a complete daily examination of the blood; and a study 

 of the mechanics of respiration including the ventilation of the lungs, the respira- 

 tion-rate, and the alveolar air. Records of the subject's mental attitude toward 

 the fast were kept, together with a series of psychological tests. Observations 

 were also made of the intestinal flora and the excretion through the skin. A com- 

 plete chemical examination of the urine was carried out by modern methods, which 

 included determinations of the various nitrogenous compounds, acid and basic 

 radicles, carbon and energy and the microscopy of the urine. An extended study 



