_Disease of the pancreas a cause of diabetes._--The pancreas, whose removal Minkowski showed caused diabetes, is located in the abdomen near the stomach and pours its digestive juices through a channel or duct into the intestine. The organ has a second function, as has been told above, namely, to make insulin. This second product, which is elaborated by the islands of Langerhans, goes into the blood. The Langerhans islands are properly regarded as a distinct and separate organ. They are, however, so intimately associated and intermingled with the rest of the pancreas that any disease or injury of the pancreas may affect them seriously, reduce their insulin-making capacity and thus cause diabetes. Actually a large part of the pancreas may be destroyed before diabetes results. In dogs, little more than one-tenth of the gland remaining intact is sufficient to prevent the excretion of sugar. Men are more susceptible to diabetes than dogs, but even in men the pancreas may be seriously affected by inflammation or cancer before its insulin capacity is reduced to the point where actual insulin shortage is manifest. The body is so constructed that every organ has a factor of safety. A very large amount of the liver, for instance, can be diseased before any failure in its function is detectable. The same is true of the kidneys and of the heart, and the factor of safety in the case of the pancreas explains why we do not all have diabetes. Very few people have a normal pancreas, because inflammations in organs near the pancreas are fairly common; for instance, inflammation of the gallbladder, and very frequently the pancreas is involved in such inflammation. However, the number of persons with known gallbladder disease who develop diabetes, is not appreciably greater than that of persons without any evidence of such inflammations. _Hardening of arteries a cause of diabetes._--The pancreas may be injured, as is true of all of the organs of the body, by disturbance of its blood supply, especially through hardening of the walls of the arterial tubes which bring it its blood, and narrowing of their lumens or passageways. Older persons with hardened arteries may develop diabetes in this manner. On the other hand, many persons have extreme arterial disease and consequent destruction of pancreatic islands without diabetes. _Infections a cause of diabetes._--The delicate tissues of the pancreas, just as in the case of other organs, may be poisoned in the course of a general disease, such as scarlet fever, mumps, or influenza and, in consequence, diabetes may result from such diseases. There is, however, nothing specific in this. A certain number of cases of diabetes can be traced to a preceding acute intoxication of this character, but it is by no means true that any one of the known infections is always followed by diabetes.