872 EXPERIMENT STATION RECOED. 



meuts here reported were men of normal health from 30 to 40 years of age. 

 Chauveau's respiration apparatus was used with slight modifications. 



The carbon dioxid eliminated was measured when the subject was sitting, 

 standing, lifting his feet alternately without moving from the spot, walking over 

 an 11-meter track without a burden, and walking with a knapsack weighing 

 7^ kg. on his shoulders. The excess of carbon dioxid eliminated when standing, 

 walking, etc., over that eliminated when the subject was merely sitting was 

 taken as the measure of energy expenditure for the various exercises. The 

 length of the step and the number of steps per minute were noted. 



In walking without a knapsack a rate of 130 steps per minute and each 

 0.517 meter long was found to involve the inost_ economical consumption of 

 oxygen. This the author estimates corresponds to walking at the rate of about 

 4.5 kilometers (2.8 miles) per hour. Increasing the rate above this produced a 

 rapid increase of expenditure, that at 7 kilometers per hour being twice that at 

 4.5 kilometers. When the knapsack was worn the most economical rate was 

 found to be 2.5 kilometers per hour, but the increase in energy expenditure did 

 not become great until 4.5 kilometers had been reached. After that the rise 

 was rapid. (See also E. S. R.. 25, pp. 269, 270.) 



Energy expenditure in walking as affected by speed and burden carried, 

 E. Bbezina and W. Kolmer (Biocficni. Zffichr., 38 {1912), No. 1-2, pp. 129-153, 

 dgms. 9; 06'?. in ZmtU. Biochcm. u. Biophys., 12 {1912), No. 19-20, p. 188).— 

 The respiratory quotient was measured with a portable respiration apparatus. 



Among the conclusions drawn are the following: The most economical speed 

 for a subject walking without burden or carrying a light load (up to 21 kg.) 

 was found to be about 85 meters (about 279 ft.) per minute, the value being 

 lower when a heavier load was carried. With increased burden the respiratory 

 volume per minute was incrensed both as to frequency and depth of respiration. 



A new form of differential microcalorimeter, for the estima'tlon of heat 

 production in physiological, bacteriological, or ferraent actions, A. V. Hill 

 {Jour. Physiol., 43 {1911), No. 3-^, pp. 261-285, dgnis. 11).— A microcalorim- 

 eter of special construction is described and experiments briefly reported on 

 various topics, among them the heat production during the souring of milk ; 

 the heat production of yeast cells acting on cane sugar, particularly the effect 

 on heat production of increasing the concentration of the sugar used ; and the 

 action of saliva on starch. 



In the last mentioned tests attention is directed particularly to the fact that 

 the heat production is extraordinarily small. " The combustion energy of 

 starch is some 5,000 calories per gram. The heat lost in the transformation 

 of starch into maltose we know is very small ; that it should be so small how- 

 ever — only some 1/10,000 of the total energy of the starch — speaks very sug- 

 gestively as to its suitability to the plant as a store of energy. Starch and 

 maltose seem to be mutually transformable, practically without energy 

 changes of loss — just as pence into shillings and shillings into pence." 



Calorimetric methods, W. Glikin {KalorimetriscJie Mcthodik. Berlin, 1911, 

 pp. VII+208, figs. 51). — Heat of combustion, heat of solution, calorimeters, 

 metliods of making corrections in calculating the heat loss of calorimeters, 

 methods for estimating heat of combustion, adiabatic calorimeters, measuring 

 the heat production of the animal body, and other similar topics are considered 

 in this summary of data. Tables are also given showing the heat of combus- 

 tion of a large number of organic compounds and foodstuffs, the heat of solu- 

 tion of organic compounds, and similar data. 



Appai'ently, the author's attention has not been directed to some of the later 

 calorimetric work carried on in the United States. 



