LTHOUGH IT IS usual to introduce a paper dealing with lymphatic tissue by A calling attention to our lack of knowledge concerning this tissue, the author wishes to take a more positive approach. He has found it impossible to present more than a few of the vast number of facts available in the literature concerning the hormonal control of lymphatic tissue. The material reviewed will be confined to the influence of hormones on the involution and growth of lymphatic tissue and on the structure and number of circulating lymphocytes. The functional significance of hormonally induced acute involution which involves such problems as the role of lymphatic tissue in the synthesis and release of certain serum proteins and also its role in the bodily economy have been recently reviewed elsewhere (185).