(32 EXPERIMENT STATION RECORD. 



a pointer attached to the other arm traces a curve on a drum covered with blackened 

 paper. After the apparatus was calibrated it was tested and found to be very 

 accurate. 



About L'o experiments were made to determine the general course of the changes 

 in the output of carbon dioxid resulting from work, which was performed on a sta- 

 tionary bicycle. The working periods in some of the experiments covered 3.0 to 45 

 minutes. A large number of experiments were also made to show how soon the 

 effect of muscular work is noted in the carbon dioxid output. The general conclu- 

 sions which were drawn from the experiments follow: 



"The problem of finding the changes in rate of output of carbon dioxid resulting 

 from muscular work and other causes is practically solved by the method used in 

 this research. The latent period of increase in output of carbon dioxid from the 

 lungs in case of beginning work is in the close vicinity of 20 seconds, and the increase 

 reaches its maximum in about 2 minutes. The output of carbon dioxid from the 

 lungs is practically uniform from minute to minute during uniform muscular work, 

 after the blood has had time to take part fully in the process of elimination. Upon 

 cessation of work the output of carbon dioxid decreases to the normal amount in 

 about the time occupied by its increase and after a like latent period. The results 

 obtained show no indication of any connection of cause and effect between the pro- 

 duction and elimination of carbon dioxid and the secondary rise of pulse rate. ' ' 



The minimum amount of protein in the daily diet, H. Labbe (Rev. Soc. Sci. 

 Hyg. Aliment., 1 (1904), No. 4, pp- 311-328, dgm. J). — An experiment is reported in 

 which the subject, a healthy man, lived upon a simple diet of bread, butter, choco- 

 late, wine, chestnuts, vegetables, and fruits. 



At the beginning of the test, which covered 38 days, the daily diet furnished a 

 little over 14 gin. nitrogen. The amount was diminished until toward the end of 

 the test it reached a minimum of 1.06 gm. It was then increased and on the last 

 day reached 13.25 gm. The amount of nitrogen and urea eliminated in the urine 

 and the income and outgo of chlorin are recorded. The energy value of the diet was 

 also calculated at different periods. At the beginning of the test the subject weighed 

 in round numbers 65 kg. and 3 days before the close 63 kg. 



In the author's opinion the experiment showed that nitrogen equilibrium can be 

 established and maintained for a long period on a limited protein ration derived 

 entirely from vegetable sources. This indicates that vegetable protein is as valuable 

 as that from animal foods. The nitrogen excreted in the urine other than in the 

 form of urea is discussed, the author pointing out that the quantity is remarkably 

 constant. The experiment is discussed with reference to the lowest protein limit in 

 the diet. 



Concerning the minimum amount of nitrog'en required per day in a con- 

 dition of rest and work, A. Gautier (Rec. Soc. Sci. Hyg. Aliment., 1 (1904), No. 4, 

 pp. 329-331). — A critical discussion of the experiment reported above. The author 

 does not agree with all the conclusions reached. 



An excess of chlorin in the diet for fifty-one days, L. Ambard (Compt. Rend. 

 Soc. Biol. [Paris], 58 {1905), No. 8, pp. 375, 376).— Chlorin equilibrium was studied 

 when an excess was consumed, and also the effect of sodium sulphate and potassium 

 nitrate on the elimination of sodium chlorid, the author being himself the subject. 



When about 1.75 gm. sodium chlorid was taken the daily excretion in the urine 

 was fairly constant during two periods, being about 2.2 gm. per day. In a third 

 period it was 1.55 gm. When 10 gm. sodium sulphate was added to the diet the 

 chlorin elimination diminished somewhat. Three grams potassium nitrate daily did 

 not increase the excretion of sodium chlorid appreciably. During part of the time 

 the sodium chlorid in the feces was found to average 0.1 gm. per day. 



