170 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



influences. In experimenting upon different kinds of bread, 

 Meyer found that white wheat bread was taken up in the 

 greatest amount during its passage through the alimentary 

 canal ; next to this, leavened rye bread ; then the rye pre- 

 pared by the Horsford process ; and, finally, the North Ger- 

 man black bread. With all these differences, however, the 

 first kind is said to be less satisfying to the feeling of hunger 

 than the other three, and to be more expensive in every point 

 of view. Meyer does not admit that bran has the nutritious 

 value claimed for it by many persons, since the nitrogenous 

 compounds it contains are mingled with much non-assimila- 

 ble matter. 12 A, April 20, 497. 



PARKES OX EFFECT OF DIET AND EXERCISE ON ELIMIMATION 



OF NITROGEN. 



Dr. Parkes, while investigating the effect of diet and exer- 

 cise on the elimination of nitrogen, had for his subject a very 

 healthy, powerful, and temperate young soldier. He conduct- 

 ed one series of experiments in which the man was fed on or- 

 dinary diet, and the amount of nitrogen-content w T as kept as 

 near as possible constant. In a second series prepared food 

 was given so as to keep the amount of nitrogen introduced 

 perfectly constant ; and a third series was made with non- 

 nitrogenous food. These experiments show T ed distinctly an 

 increased elimination of nitrogen in the period of rest after 

 severe exercise, confirming Dr. Parkes's former results, and 

 supporting the statement of Liebig on this point, in opposi- 

 tion to that of Voit. Whether it was diminished during ex- 

 ercise or not was not clearly shown by the experiments. 

 The non-nitrogenous diet for five days neither raised nor low T - 

 ered the temperature in the rectum of the patient, but appar- 

 ently did not affect the health, nor did it alter the frequency 

 of the pulse ; but the heart's action became weak, and the 

 pulse soft. The experiments proved that force necessary for 

 great muscular work can be obtained by the muscle from fat 

 and starch, though changes in the nitrogenous constituents 

 of the muscles also go on, which have, as one effect, an in- 

 creased elimination of nitrogen after the cessation of the 

 work. 21 A, June, 413. 



