In the past twenty years, a vast amount of work has been done which has broadened our views concerning tetany. Recently, this extensive literature was reviewed and correlated by MacCallum,1 himself one of the foremost contributors. He pointed out that "there may be several types of tetany differing widely in their etiology and in the mechanism of their production although the final changes in the blood which bring about the actual symptoms may be the same." He agreed with Aschenheim that those cases of tetany that are related to the psychoses, infections, intoxications and endocrine disorders can be classified only tentatively, but he demonstrated at least four well studied types: (1) that resulting from extirpation of the parathyroid glands, (2) gastric tetany, (3) tetany from forced respiration and (4) infantile tetany or spasmophilia. He also pointed out the possibility that other types are produced by modification of the diet