Diabetes: its pathological physiology / by John J.R. Macleod.

  • Macleod, J. J. R. (John James Rickard), 1876-1935.
Date:
1913
Catalogue details

Licence: In copyright

Credit: Diabetes: its pathological physiology / by John J.R. Macleod. Source: Wellcome Collection.

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    disease. By comparing the metabolism of the diseased animal with that of one that is normal, a great deal about the function of the particular organ or tissue that is damaged can frequently be learned. Among the simplest of the chemical substances which take part in the chemical processes occurring in the animal body are the carbohydrates, and a very important chapter in modern biochemical research is concerned with the changes which these bodies undergo in the animal body. The healthy normal animal is able to oxidize completely very large amounts of carbohydrate, but this ability may become depressed, and the unused carbohydrate appear in the urine as dextrose. This condition of glycosuria, as it is called, is readily detected, and its development serves, therefore, as a valuable indicator of the state of carbohydrate metabolism. In the disease known as “ diabetes mellitus,” glycosuria is a most important symptom, and by observing its intensity under various conditions of diet, an immense amount of valuable information, concerning the possible sources of carbohydrate in the body, has been derived, and great progress has been made in the treatment of the disease. In the investigation of the problems of carbohydrate metab- olism, experimental and clinical investigation must therefore go hand in hand. The results obtained in the laboratory must be supplemented by observations at the bedside, not only in order that we may obtain every possible piece of information regarding the nature of the conditions which cause the disordered metabolism, but in order that we may learn how to correct the fault that exists, and therefore alleviate, if not cure, the disease. Although we cannot hope to accomplish this with any degree of certainty until we possess a clear understanding of the nor- mal metabolism of carbohydrate, it is striking how much has already been accomplished. A few remarks bearing on this aspect of our subject, as illustrating the value of co-ordinated clinical and experimental investigation, may not be out of place. It is now recognized that in the earlier stages of most forms of diabetes no other symptom of a deranged metabolism exists than the inability of the organism to assimilate amounts of carbohydrate which can readily be tolerated in health. So long as the diet contains less than this “ assimilation limit,” the urine remains sugar-free, and the person is to all intents healthy,