On the food of man in relation to his useful work / by Lyon Playfair.

  • Lyon Playfair, 1st Baron Playfair
Date:
1865
Catalogue details

Licence: Public Domain Mark

Credit: On the food of man in relation to his useful work / by Lyon Playfair. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    of urea from the system is sometimes retarded two days. Hammonds experiments, even upon the same diet, were however very conclusive. His results are as follow :— Urea. Uric Acid. With no exercise, . 487-0 grs. 24-9 grs. Moderate „ . 6821 „ 13-7 „ Hard „ . 865-0 „ 8-2 „ 31. When a large amount of animal diet is the chief source of food, exercise becomes a necessity, in order to waste the tissues for the support of respiration and other vital movements. Without it^the animal soon loathes the food. This is not only the experience of carnivora, but also of man. Darwin tells us that, when in the Pampas, he lived tolerably well on a meat diet, but felt that it would only agree with me with hard exercise and he tells us that the Guachos, who live upon meat, eat largely of fat, probably not only for respiratory food] but also as a protection against unnecessary muscular waste, as we have explained. Sir John Richardson observed the same fact in his Arctic travels, havino- noticed that when people have fed a long time solely upon lean animal food, the desire for fat becomes so in- satiable that they can consume a large quantity of un- mixed, and even only fat, without nausea. The hyena m confinement wastes its tissues by moving backwards and forwards incessantly in its den, and thus is able to consume its animal diet. All this shows that the normal function of nutrition is to build in plastic food into tissues, to be transformed by internal and external dynamical work into carbonic acid, water, and urea 32. We have confined our attention chiefly to urea because, as a representative of dynamical labour, it is
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