788 EXPERIMENT STATION RECORD. 



Experiments on the metabolism of nitrogen, sulphur, and phosphorus in 

 the human organism, II. C. S^iiermax [U. S. Dejit. Agr., Office of Experiment 

 Stations Bill. 1/1, pp. 47, (J(jmi^. 3). — The digestibility of a simple mixed diet, and 

 the income and outgo of nitrogen, sulphur, and phosphorus were studied in 10 

 experiments of which the author was the su))ject. The comparative digestibility of 

 liberal and restricted diet and the effects of loss of sleep were also studied. The 

 diet consisted of bread (crackers) and milk, with butter added in some of the tests. 

 The author regards additional experiments necessary l)efore final deductions can Ije 

 drawn, but sunmiarizes the principal results as follows: 



"The proportions of protein digested irom a restricted diet were about 0.7 per cent 

 higher than those digested from a liberal diet of the same composition. 



"Marked loss of sleep for .3 successive nights resulted in a small increase in the 

 amounts of nitrogen, sulphur, and phosphorus excreted. The increase of sulphur 

 was proportional to that of nitrogen, and the increase of phosphorus was very slightly 

 larger, the relative differeni'e being no greater than might be attributed to the usual 

 daily variations. The increased elimination resulting from loss of sleep did not 

 appear until the third day, while changes resulting from alteration of the diet were 

 alwaj's perceptible on the first day. 



"The data collected regarding the relative 'lag' of nitrogen, sulphur, and phos- 

 phorus are not yet sufficient to permit general conclusions to be drawn. 



"In general the metabolism and 'balance' of sulphur ran approximately parallel 

 with that of nitrogen. The renal elimination and 'balance' of phosphorus showed 

 fluctuations similar to those of nitrogen, but not so closely parallel as in the case of 

 sulphur. The elimination of phosphorus by the intestine was large and variable, 

 making the accurate separation of the feces an important factor in the determination 

 of the i)hosphorus balance." 



The results attending- the use of a diet suflB.cient for maintenance but poor 

 in protein, B. H, Jagerroos {Skand. Arch. PhiisioL, 13 {1902), No. 6,p}). 375-418).— 

 The author reports exj)eriinents with dogs in which the animals lived for a number 

 of months on a diet furnishing as low as 0.2 gm. nitrogen per kilogram body weight 

 and finally died from some infectious disease. The balance of income and outgo of 

 nitrogen was determined. The diet after a time was not relished and the dogs with 

 difficulty could be induced to eat it, which in the author's opinion showed that it 

 was not satisfactory. He holds that if a daily diet fulfills hygienic requirements, is 

 sufficiently abundant, palatable, easily digested, composed of fresh materials, and 

 of suitable volume, no special attention need be paid to the protein content, as a 

 sufficient amount will undoubtedly be furnished. 



The excretion of carbon dioxid and water by man through the skin, E. A. 

 VON WiLLEBRAND {SLxtud. Arcli. Fhi/.voL, 13 {1902), No. 6, pp. 337-358, fgs. 3).— In 

 the experiments reported the body of the subject was inclosed in a metallic box or 

 chaml>er, the head protruding through the top. There were devices for drawing a 

 current of air through this chamber and collecting and analyzing it, the apparatus 

 and methods being described. From the author's experiments he concludetl that 

 the excretion of water through the skin during absolute rest is moderate and is pro- 

 portional to the temperature of the surrounding air, increasing from 12° C. to the 

 point at which the temperature is great enough to cause perspiration. An abundant 

 secretion of perspiration is observed between 30 and 33° C. The amount of car- 

 bon dioxid excreted through the skin remains constant at a temperature of from 

 20 to 33° C, during absolute rest being equal to 7 or 8 gm. in 24 hours. If the 

 temperature rises to such a point that perspiration is induced, the amount of carbon 

 dioxid increases suddenly to 3 or 4 times its former value. The author's investiga- 

 tions do not show how carbon dioxid is excreted through the skin, but he offers the 

 suggestion that some of this gas, which is present in the blood, reaches the surface 

 of the body by diffusion. He discusses also the source of the water excreted as 

 perspiration. 



