Structure of Lymphocytic Series of Cells in Relation to Disease 279 



finding of a roughly equal admixture of lymphoblasts, prolymphocytes, 

 and mature lymphocytes. 



MATURE LYMPHOCYTES 



Prolymphocytes normally can form other prolymphocytes by mitosis 

 (Table 19-1) or can transform into large, medium-sized, and small mature 

 or adult lymphocytes (cf. peripheral coarsely nucleated cells in Figs. 19-1, 



15 . 



Fig. 19-15. A group of leukemia prolymphocytes from the blood in 

 a case of subacute lymphocytic leukemia. Leishman stain, (x 1100) 



19-2, 19-18). Students of this field do not question the ability of the reticulum 

 cell, lymphoblast, prolymphocyte, and large adult lymphocyte to undergo 

 mitotic division. That the medium-sized and small nonleukemic and non- 

 malignant lymphocytes are similarly capable of reproducing themselves has 

 been disputed or denied. It is now known that because of the unexpectedly 

 long life span of the mature lymphocytes revealed by the radioisotopic 

 investigations of Ottesen 4 - and Hamilton,- 7 mitotic figures among these cells 

 are not numerous and do not need to be. However, study of imprinted 

 lymph nodes in nonmalignant conditions affords ample opportunity to 

 demonstrate mitoses in medium-sized (Fig. 19-11) and small, mature lym- 

 phocytes (Fig. 19-13 between the two central prolymphocytes). 



In the lymphocytic tissues large, medium-sized, and small, mature or adult 

 lymphocytes will be found. Normally only the medium-sized and small, 

 mature lymphocytes are present in the blood. Size, however, is a relatively 



