Food in its relations to various exigencies of the animal body / by J.B. Lawes and J.H. Gilbert.

  • Lawes, J. B. (John Bennet), 1814-1900.
Date:
1866
Catalogue details

Licence: Public Domain Mark

Credit: Food in its relations to various exigencies of the animal body / by J.B. Lawes and J.H. Gilbert. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    “ As an immediate effect of the manifestation of mechanical force, we see, that apart of the muscular substance loses its vital properties, its character of life; that this portion separates from the living part, and loses its capacity of growth and its power of resistance. We find that this change of properties is accompanied by the entrance of a foreign body (oxygen) into the composition of the muscular fibre (just as the acid lost its chemical character by combining with zinc); and all experience proves, that this conversion of living muscular fibre into compounds destitute of vitality is accelerated or retarded according to the amount of force employed to produce motion. Nay, it may safely be affirmed, that they are mutually proportional; that a rapid transformation of muscular fibre, or, as it may be called, a rapid change of mat- ter, determines a greater amount of mechanical force; and con- versely, that a greater amount of mechanical motion (of mecha- nical force expended in motion) determines a more rapid change of matter.” (Organic Chemistry in its applications to Physio- logy and Pathology, 1842, pp. 220 & 221.) And again:— “The amount of azotized food necessary to restore the equili- brium between waste and supply is directly proportional to the amount of tissues metamorphosed. “ The amount of living matter, which in the body loses the con- dition of life, is, in equal temperatures, directly proportional to the mechanical effects produced in a given time. “ The amount of tissue metamorphosed in a given time may be measured by the quantity of nitrogen in the urine. “ The sum of the mechanical effects produced in two indivi- duals, in the same temperature, is proportional to the amount of nitrogen in their urine; whether the mechanical force has been employed in voluntary or involuntary motions, whether it has been consumed by the limbs or by the heart and other viscera.” (Ibid. p. 245.) Our own direct experiments have had reference chiefly to the feeding of fattening animals; but the characteristic food require- ments of the body, when fed with the view to the exercise of muscular power, have also been made the subjects of inquiry. Referring to the feeding of fattening animals, the question arises, whether in the use of the currently adopted food-stuffs the amount of food consumed by a given weight of animal within a given time, and the amount of increase produced are more influ- enced by the amount of the nitrogenous or of the non-nitroge- nous constituents which the food supplies; that is to say, whether the sum of the requirements of the animal system under these circumstances is such that, in the use of the ordi- nary articles of food, the amount taken or inci'ease produced will