ANIMAL PRODUCTION. 757 



tempt to secure a measure of the proportion of fat to active tissue. Full experi- 

 mental data are reported from which the authors draw in part the following 

 conclusions : 



" The specific gravity, even if accurately measured, can not serve as a measure 

 of the proportion of fat to active tissue. . . . 



"The heat production for the sleeping period averages for the 10 children 

 2.7 calories per kilogram and hour. It is highest on this basis for the atrophic 

 and underweight children and lowest for the fattest child. On the basis of a 

 square meter of surface the heat production of normal children shows a decided 

 increase from the early months (2 to 4) to the later mouths (6 to 12) of the first 

 year. The average of all the 10 children is 39.7 calories. The average deviation 

 from the mean heat production in all sleeping periods is about ±10 per cent for 

 each of the several formulas expressing the relation of surface area to weight." 



Practically the same average heat production per unit of weight and per unit 

 of surface was obtained when all the infants between 2 months and 12 months 

 in this series and in the experiments of others (61 in all) were compared, i. e., 

 2.7 calories per kilogram and hour, 39.3 calories per square meter and hour. 



" On the unit of weight all but 3 of the atrophic and underweight children 

 (48 in all) lie above the line represented by 2.5 calories per kilogram and hour; 

 all the normals (18) lie near this line; and all but 1 of the overweight infants 

 (5) lie below the line. Two and one-half calories per kilogram and hour or 60 

 calories per kilogram and 24 hours may therefore be called tentatively the ' nor- 

 mal heat production ' of recently fed, sleeping infants between 2 months and 1 

 year of age. Included in this figure is whatever dynamic action the foods them- 

 selves may have; otherwise the figure is minimal. Hard crying may increase 

 the metabolism as much as 40 per cent ; the requirement for growth and allow- 

 ance for nonabsorption must be added. . . . 



" There seems to be no sufficient reason . . . for estimating the food require- 

 ments of infants on the basis of surface area rather than on the basis of 

 weight." 



A calorimetric calibration of the Krogh, bicycle ergometer, F. G. Benedict 

 and L. E. Emmes (Amer. Jour. Physiol., 38 {1915), No. 1, pp. 52-61, figs. 2). — ^A 

 report of the calibration of an electric brake bicycle ergometer, which has pre- 

 viously been described by Krogh (E. S. R., 30, p. 767). 



The ergometer, placed in a calorimeter, was rotated ftom the outside by a 

 motor. The heat developed, as measured by the calorimeter, was compared 

 with the computed work done in sustaining various loads on a suspended bal- 

 ance pan. Tests were made at different rates of speed and with different 

 weights on the balance pan. " These experiments showed that friction and 

 other extraneous factors may be entirely neglected in using the Krogh bicycle 

 ergometer and that the results obtained by calibration were within 0.5 per cent 

 of theory." 



ANIMAL PRODUCTION. 



Further experiments on the inheritance of coat color in rabbits, R. C. 

 PuNNETT (Jour. Genetics, 5 (1915), No 1, pp. 31-50). — Continuing work previ- 

 ously noted (E. S. R., 28, p. 768), the author reports further experiments with 

 rabbits showing the unexpected appearance of agoutis in litters from black 

 parents. He also gives results of experiments showing that chocolate in the 

 rabbit, as in the mouse, behaves as a simple recessive to black and that the 

 chocolate series of colors runs strictly parallel with the black series. These 

 data are interpreted on both the " presence and absence " and the " multiple 

 allelomorph " hypotheses, but reasoning is advanced to show that it would ap- 



