Mercers' company lectures on recent advances in the physiology of digestion : delivered in the Michaelmas term, 1905, in the Physiological Department of University College, London / By Ernest H. Starling.

  • Starling, Ernest Henry, 1866-1927.
Date:
1906
Catalogue details

Licence: Public Domain Mark

Credit: Mercers' company lectures on recent advances in the physiology of digestion : delivered in the Michaelmas term, 1905, in the Physiological Department of University College, London / By Ernest H. Starling. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    the active part of the organism, consists almost entirely of proteids or allied bodies. Fats and carbohydrates, where they occur in the living organism, are found only to a slight extent in combination in the living protoplasm itself, the greater part of them being laid down as store material for the future wants of the active growing protoplasm. Many facts show that the combustion and utilisation of the energy of the carbon and hydrogen of the food take place in the protoplasm itself, the oxidisable molecules being linked on to the central living nucleus; and it seems that nitrogen plays an important part both in this linkage, and in bestowing on the complex thus pro- duced the labiHty or instability which is a necessary condition of the vital processes themselves. Essential functions of all living beings are those of growth, repair, and in the higher animals death. No act can go on without involving some degree of disintegration of the living nitrogenous framework of the tissue, and the consequent need of repair. In every living cell, therefore, we may speak of tw^o kinds of chemical changes, or of tw^o destinations of the food- stuffs. In the first place there are the changes which furnish the energy necessary for vital manifestations, movement, warmth, etc. As sources of this energy, all three classes of food-stuffs can be employed, their value being given by their heat equivalents when taken as food. In the second place we have the changes which are involved in the disintegration, repair, and growth of the living protoplasm itself. In this nutritional metabolism proteids play the most important part, and are absolutely essential for the continuance of life. An animal, therefore, can theoretically be nourished on a diet of pure proteid, but it would be impossible to keep an animal alive on a diet consisting either of pure fat or of pure carbohydrate. These three classes of food-stuffs being essential constituents of all our foods, the use of the processes of digestion is to