88 The Lymphocyte and Lymphocytic Tissue 



were scarce, and almost as many plasma cells as preplasma cells were present. 

 At this time fluorescent staining of antibody reached a peak in the sites (Fig. 

 7-5). By the eighth or ninth days after transfer, virtually all the cells in the 

 transfer sites were plasma cells, but fluorescent staining of antibody was 

 waning (Figs. 7-6 through 7-9). 



Fig. 7-3. Frozen tissue section of cell transfer on the fifth day, stained for anti-BSA. 

 Note the increased number of positive cells around a medium-sized blood vessel as 

 compared to the third day (Fig. 7-4). (x 500) 



Mitotic acti\ itv in the sites was minimal throughout the period of observa- 

 tion. Although an occasional binucleate cell was observed on tissue smears, 

 no mitoses were found. When mitotic counts were made on the fixed sites, 

 no more than one mitosis per 500 cell nuclei was observed, and mitoses in 

 the sites of killed cells were about as common (or uncommon) as in the sites 

 of live cells. 



