NUTRITION LABORATORY. 303 



(3) Carbon-dioxid content of barn air. Mary F. Hendry and Alice Johnson. Journ. 



Agric. Research, vol. 20, p. 405 (1920). 



The construction of a large respiration chamber in the dairy barn of the 

 Agricultural Experiment Station at Durham, New Hampshire, led to an 

 investigation of the carbon-dioxide content of the air and its probable in- 

 fluence upon respiration experiments in case such air should inadvertently 

 leak into the chamber. A series of analyses extending over all hours of the 

 day and night showed a percentage of carbon dioxide ranging between 0.089 

 and 0.228. It is clear that there is a large percentage of carbon dioxide in the 

 air of this modern barn, but its presence has had no apparent influence upon 

 the health of the animals during the two decades that the building has been 

 occupied. This fact is not without significance in the question of the venti- 

 lation of rooms occupied by humans. 



(4) Tables, factors, and formulas for computing respiratory exchange and biological trans- 



formations of energy. Thorne M. Carpeiiter. Carnegie Inst. Wash. Pub. No. 303 

 (1921). 



This pubUcation is a compilation of tables, factors, and formulas which have 

 been found to be of service in the calculation of results from data obtained 

 with the various forms of respiration apparatus used with men and animals. 

 A description of the tables is followed by a group of tables useful in the re- 

 duction to 0° C. dry and 760 mm. mercury-pressure of gas-volumes, either 

 partially saturated with water-vapor as in a chamber, or completely saturated 

 as is expired air collected in a spirometer. The various reUable factors and 

 formulas for obtaining body-surface of man are given, followed by the stand- 

 ards (tables and formulas) for predicting the basal heat-production per 

 24 hours of all ages of both sexes, available up to the time of publication 

 (Harris and Benedict, Benedict and collaborators, Aub and Du Bois, and 

 Dreyer) . The compilation concludes with a series of tables giving the factors 

 for converting various units of work, energy, and measures into one another. 



(5) The variation and the statistical constants of basal metabolism in men. J. Arthur 



Harris and F. G. Benedict. Journ. Biol. Chem., vol. 46, p. 257 (1921). 



In all special investigations in human calorimetry some standard constant 

 measuring the metabolism of the normal individual must be used as a basis 

 of comparison. The selection of this constant presents a problem of some 

 difficulty, as consideration should be given to the physiological conditions 

 under which the measurements were made, the unit in which the caloric 

 output shall be expressed, and the method by which the statistical constants 

 for the standard series shall be obtained. It may be reasonably assumed 

 that the results of the several periods of measurement on a given day stand 

 in the relation of duplicate, tripUcate, etc., analyses. The special purpose 

 of this paper has been to investigate the variability in the basal metabolism 

 of the normal individual and the method of determining a population mean 

 from a series of individual constants. The average of daily periods of ob- 

 servation for individual men who have been studied from 20 to 53 days shows 

 that the variabiUty is measured by coefficients of variation of about 4 per 

 cent of the average metabolism. The correlations between range of observa- 

 tions and variations in metabolism are greater for narrow ranges of observa- 

 tion than for the longer ranges, thus indicating that the greater part of the 

 physiological variations in metaboUsm will be reahzed in relatively short 

 periods of time. It is evident, therefore, that the metaboHsm of the normal 

 subject is not constant, even with practically constant body-mass, but is to 

 some extent in a state of flux. The results of this study also show that the 

 population constant derived from individual means is less modified by weight- 



