EXPERIMENTAL STUDIES ON THE CHIEF SOURCE OF BLOOD LYMHOPCYTES IN ADULT RABBITS

In adult rabbita,chief lymphoid organs such as the mesenterial lymph nodes,vermiform appendix and apleen,sa well as other several small lymph nodes,were removed.Ｔｈｅ total weight of the removed lymphoid organs amounted to approximately 80 per cent of that of the entire lymphoid organs.In the rabbit the mesenterial lymph nodes unite in a large mass called panereas Aselli,the weight of which is adout one and a half of the other lymph nodes. Simulataneous extirpation of The chief lymphoid organs mentioned adove and other sevecal small lymph nodea resulted in a marked drop of The mumber of the blood lymphocytes,down to 30 to 40 per cent of the pre-operative values,and such a pronounced lymphopesnia persisted for several weeks.No other remaekable alterations were observed in the blood picture, except for a post-operative nonspecific granulocytosis which subsided rapidly.The continuity of The lymphatic pathway interrupted by the removal of the mesenterial nodes has been rapidly re-estabulished. Removal of The mesenterial mass of lymph nodes alpne was respousible for a marked fall of the blood lymphocyte counta ,so long as this mass was well developed and ita weight greater than 1/200 of the body weight.But when The relative weight of this mass was below this level,The removal of this mass was followed by little or no reducation of the blood lymphocytes. Appendectomy combined with splenectomy alone caused no significant drop of The blood lymphocyte counts.However,when the mesenterial mass of nodes was too small in size to induce a perceptible lymphopenia after its removal,The subsequent extirpation of The vermiform appendix and spleen on the 7th day produced a remarkeable reduction of the blood lymphocytes. Those finding indicate that,in The rabbit,The mesenterial mass of lymph nodes representa The chief sourcc of The blood lymphoctyes together with The vermiform appendix and spleen,the latter organs being auxiliary to the former one.