This is apparently a reprint of a semipopular lecture on metabolic diseases and heredity, with particular reference to diabetes mellitus. It is one of a series of pamphlets published in the interests of "race hygiene." The author cursorily reviews the evidence for the influence of heredity on the incidence of diabetes and attempts to show that this same hereditary factor also predisposes to obesity, the arthritides and nervous disorders. He concludes that young persons with diabetes should be discouraged from marriage and that the mating of members of "diabetic families" should be strictly forbidden. A bibliography is appended in which the only non-German reference is a book by Joslin, not correctly titled and incompletely cited.