The anatomic and functional independence of the thyroid and the parathyroid glands may be regarded as definitely established. It is also certain that the acute nervous manifestations which follow the removal of both organs in carnivorous animals are due to the absence of the parathyroid glands. However, the function of these glands is still an open question, and the pathogenesis of the usually fatal tetany which follows their complete removal is not satisfactorily explained. A number of theories have been advanced from time to time, but since these have been carefully summarized in several recent reviews,1 reference will be made only to those that have become of interest in my own experiments.
In conformance with the prevailing ideas regarding the possible functions of ductless glands, it is possible that the parathyroids contribute some substance to the blood which is necessary for life, and in the absence of which the