An introduction to the study of secretion / by Swale Vincent.

  • Vincent, Swale, 1868-1934.
Date:
1924
Catalogue details

Licence: In copyright

Credit: An introduction to the study of secretion / by Swale Vincent. Source: Wellcome Collection.

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    have yet no evidence, direct or indirect, sufficiently convincing to prove that under ordinary conditions the chromaphil tissues are necessary to the efficient working of the body. 7. The Islets of Langerhans It was long ago suggested by Schafer that the internal secretion of the pancreas is produced by the islets of Langerhans, and in 1916 the same author employed the name “ insulin ” for the hypothetical substance secreted by the islets. This name has recently been applied by Banting and Macleod to the pancreatic preparation which has the power of reducing the blood-sugar when injected beneath the skin of an animal, and which is now being employed as a remedy for diabetes. Minkowski and Mehring 98 first showed that complete removal of the pancreas in the dog, cat, and pig is followed by diabetes. That this is caused by the absence of an internal secretion is proved by the facts that it does not occur if the gland be left in situ and the duct tied, nor does it occur if a portion of the pancreas be grafted in some situation remote from its normal position (e.g. underneath the skin or in the peritoneum). How the internal secretion of the pancreas normally prevents glycosuria is not yet clear. The evidences that the islets and not the pancreas as a whole are concerned with the internal secretion are as follows : it is stated that in disease of the pancreas associated with diabetes, it is the islets rather than the zymogenous tissue which are affected. When the duct of the gland is tied the zymogenous tissue atrophies and the animal is enabled to survive because the islets do not atrophy. Insulin has recently been extracted from a pancreas after atrophy of tubules, and from the separate islets of certain fishes, where the islets can be obtained free from zymogenous tissue. It is yet too early to discuss how insulin lowers blood-sugar, or precisely what is the effect on the progress of a case of diabetes. It is only certain that in many cases insulin will restore a diabetic patient to comparative health and comfort, but the treatment has to be continued. The chemical nature of insulin has not yet been ascer-