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September 1921


Arch Intern Med (Chic). 1921;28(3):239-251. doi:10.1001/archinte.1921.00100150002001

The histogenesis of the thymus is still a subject of debate. Most investigators are agreed that the reticulum and Hassall's corpuscles are epithelial in origin. The derivation of the chief elements of the organ, however, namely, the small cells, has not been determined. For example, Maximow1 believes that early in the process of development the thymus becomes invaded by mesenchymal elements which differentiate into lymphocytes and that these accumulate in such numbers as to give to the organ the appearance of a lymphoid structure. Maximow's belief in the lymphocytic nature of the small cells is shared by Hammar2 and Schaffer,3 but is opposed by Stöhr4 and Pappenheimer,5 who regard them as epithelial. It seems to us that the conception of the small thymic cell as a lymphocyte is more in harmony with common knowledge of the pathology of the gland, especially its tumors and, if Maximow's conception is correct, it