NUTRITION LABORATORY. 225 



PUBLICATIONS. 



(1) A portable respiration apparatus for clinical use. Francis G. Benedict. Boston Med. 



and Surg. Journ., 178, 667 (1918). 



The experience with pathological cases in the Nutrition Laboratory made 

 it evident that a simple and accurate method for determining the respiratory- 

 exchange was needed which would lend itself to more general usage than 

 either the compHcated respiration calorimeter or the somewhat less compli- 

 cated clinical respiration chamber. This led to the devising of the portable 

 respiration apparatus which is a natural development of the universal respira- 

 tion apparatus in its several forms. In the portable respiration apparatus, 

 which is described in detail in this paper, the patient breathes into and out 

 of a confined volume of air, which is circulated by means of a mechanical 

 blower through a series of purifiers in which the carbon dioxide and water- 

 vapor are absorbed. A spirometer provides suitable housing for the mechani- 

 cal blower, acts as an expansion chamber for the fluctuating volume of air, 

 and gives a measure of the changes in volume of air by means of direct read- 

 ings of the level of the spirometer bell. Attachment to the subject may be 

 made by a mouthpiece, nosepiece, or face-mask. The apparatus is mounted 

 on a convenient stand, with casters, which enables it to be moved about a 

 laboratory or hospital with perfect ease, requiring only connection with an 

 electric socket. 



The decrease in the total volume of air, as measured by the changes in 

 level of the spirometer bell with slight temperature and pressure corrections, 

 represents the amount of oxygen consumed by the patient during the experi- 

 mental period, which may continue for 10 or 15 minutes. The oxygen con- 

 sumption is thus determined without gas analysis, weighings of any kind, 

 or the use of meters. The lungs of the patient are not required to force the 

 air through the purifying vessels or to actuate valves of any kind, since this 

 is done by the electric fan located in the spirometer; hence respiration through 

 this apparatus is as nearly normal as possible. By indirect calorimetry the 

 heat-production may be computed from the oxygen consumption. While 

 primarily designed to give a measure of the oxygen consumption, since this 

 is least affected by abnormal respiration such as may occur with hospital 

 patients, an approximate measure of the carbon-dioxide elimination and 

 respiratory quotient may also be obtained by weighing the absorbing vessels. 

 " This apparatus was tested practically in the research on undernutrition, 

 in which several hundred observations were made, determinations of the 

 gaseous metabolism of seven of the subjects being obtained simultaneously 

 nearly every day of the research. The subsequent careful test of this method 

 of determining the respiratory exchange by comparison with some of the 

 older and better-known types of respiration apparatus, which was made by 

 Dr. Carpenter, is referred to in another part of this report, (See page 223.) 

 The apparatus has been found to give very satisfactory results and thus 

 makes it possible for observations of the oxygen consumption to be conducted 

 in a clinic or a private laboratory without gas analysis or weighings. 



(2) The effects of a prolonged reduced diet on twenty-five college men. I. On basal 



metabolism and nitrogen excretion. II. On neuro-muscular processes and 

 mental condition. 111. On efficiency during muscular work. Francis G. Bene- 

 dict, Walter R. Miles, Paul Roth, and H. Monmouth Smith. Proc. Nat. Acad. 

 Sci., 4, 149 (1918). 



Although the accumulation of data in the low-diet research with a selected 

 group was not finished until February 3, a preHminary report of the findings 

 of this set of results was made before the National Academy of Sciences on 



