difficult to find examples for drawing that were 

 not misshapen beyond recognition. Even m 

 figure 100 two of the projections were flattened 

 against adjacent erythrocytes. The example 

 shown is large enough to he a monocyte but its 

 structure is quite different from that of mono- 

 cytes taken from the same slide, an example of 

 which is shown in figure 125. 



In general there is less cytoplasm relative to 

 the nuclear area than in monocytes, but again 

 there is overlapping of their ranges, as may be 

 seen by comparing figures 150 and 151 and 

 graphs on figures 152 and 153. If the outline 

 drawings on these two plates were cut apart and 

 and shuffled it would be impossible to separate 

 them correctly in many cases into the two cell 

 types; this fact emphasizes the point that separa- 

 tion of lymphocytes and monocytes is based on 

 more than just size, shape, nuclear position, and 

 nucleocytosomal ratio. 



Cytoplasmic structure. — The cytoplasm may 

 stain intensely or faintly. It may be granular or 

 nearly homogeneous. The granular condition 

 is quite common and appears as a flocculation of 

 basophilic material (figs. 95-99). These fig- 

 ures illustrate variations in the size of the baso- 

 philic masses and in the intensity of staining. In 

 figure 98 the granules near the edge of the cell 

 are large and dark, tliose near the nucleus are 

 smaller. In figure 96 the basophilic material 

 gives texture to the cytoplasm but there are no 

 distinct basophilic masses. The flocculent ap- 

 pearance of the cytoplasm lies at the limit of 

 microscopic visibility and sometimes the cyto- 

 plasm appears to be a reticulum with denser 

 masses at the interstices, such as shown in figures 

 95, 99, and 101. 



All the cells mentioned so far have been stained 

 with Wright's stain. The cell in figure 91 was 

 stained with May-Griinwald Giemsa, which ac- 

 counts for a coloration different from the rest of 

 the cells. It also shows the basophilic masses in 

 the cytoplasm but here they are more nearly 

 spherical and are more definite than in the pre- 

 vious examples. 



The cytoplasm in figure 90 is nearly homo- 

 geneous with only slight irregularities in density. 

 Further change toward a hyaline structure is 

 shown in figure 100. When the cytoplasm 

 reaches this hyaline condition it tends to flow out 

 away from the nucleus. In the hyaline type, the 



quantity of cytoplasm is great enough in relation 

 to nuclear size to establish the cell as a monocyte, 

 if only the one character of nucleocytosomal ratio 

 is used for identification. 



Sometimes a lightly stained area is present in 

 the cytoplasm adjacent to the nucleus. The cell 

 in which this is illustrated (fig. 97) is classed as 

 a lymphocyte, altliough in the table on lympho- 

 cyte and monocyte characteristics, such a light 

 area is more typical of a monocyte (see, for ex- 

 ample, figs. 126, 127, 129, and 144). This is 

 another example illustrating the point that the 

 presence or absence of only a single characteris- 

 tic is insufficient basis for a satisfactory separa- 

 tion of these two cell types. Looking over the 

 entire group of lymphocytes from figure 90 to 

 figure 101, there is little question that the cyto- 

 plasmic structure of these cells is highly diverse 

 and that no narrow characterization will cover 

 them all. 



Hof and orange-stained spheres. — These are 

 characteristic of monocytes and so will be dis- 

 cussed later. Specific cytoplasmic inclusions are 

 not normally present in lymphocytes but in cells, 

 considered to be abnormal, they do exist as ma- 

 genta bodies (figs. 102-116) ; therefore the de- 

 tails of their structure will be deferred until ab- 

 normal cells are discussed. These magenta 

 bodies are almost specifically associated with 

 lymphocytes and thus are useful for identifica- 

 tion purposes. 



Nuclear shape. — The lymphocyte nucleus is 

 approximately round, as shown in figures 90, 93, 

 105, and in many of the cells in figure 150. 

 Deviations from that shape are common and, as 

 would be expected, they occur by imperceptible 

 structural differences in various directions. 

 When the nucleus is eccentrically placed, the 

 contour of the portion adjacent to the mass of 

 cytoplasm is more flattened than the remainder, 

 which is adjacent to the outside wall (figs. 97, 

 101, and 107). If the cytosome of the cell is 

 lobulated, often the contour of the nucleus is 

 irregular also but not necessarily concentric with 

 the cell outline. 



Indentation of the nucleus is not common in 

 lymphocytes but does occur sometimes (figs. 91, 

 94, 111. and 114) . Usually the depression is not 

 deep and the margins cui-ve inward to a sharp 

 angle ( V ^ ) instead of forming a de- 



52 



