A turning point in the history of diabetes mellitus took place in 1889 after the experiments of Minkowski and von Mering.

In 1886, three years before their first meeting, von Mering discovered that phlorizin, a glucoside, could cause transient glucuresis. In 1889, while von Mering was working in Hoppe Seyler’s Institute at the University of Strasbourg, Minkowski, assistant at that time to the German leading authority on diabetes Professor Bernard Naunyn (1839-1925), he visited the Institute to look at some chemical books of the library. They met accidentally and talked about Lipanin, an oil containing free fatty acids and von Mering used to administrate to patients suffering from digestive disturbances. Minkowski was not in favor of Lipanin intake and then their conversation turned on whether the pancreas had a role in digestion and absorption of fats. As a result of the discussion, the two men decided the same evening to perform a pancreatectomy in a dog in Naunyn’s laboratory. The animal remained alive and was closely observed by Minkowski, as von Mering left urgently to Colmar because of a family issue. Soon after the operation, the dog developed polyuria. Minkowski examined the urine and found that it contained 12% sugar. Initially Minkowski believed that the dog developed diabetes due to the fact that von Mering had treated it for a long time with phlorizin. So he repeated the pancreatectomy in three more dogs which had no sugar in their urine previous to operation and all of them developed glycosuria[13,16].

Furthermore Minkowski implanted a small portion of pancreas subcutaneously, in depancreatized dogs, and observed that hyperglycemia was prevented until the implant was removed or had spontaneously degenerated[13].

Minkowski and von Mering experiment demonstrated that pancreas was a gland of internal secretion important for the maintenance of glucose homeostasis. They also paved the way for Banting and Best to conduct their experiments and to meet with success.