Nonleukemic Lymphocytosis 151 



blood are so characteristic that a diagnosis of infectious mononucleosis can 

 be made from the inspection of the peripheral blood smear alone. This 

 statement is true only in a very limited sense. 



In the first place, cells which individually have the features of those seen 

 in infectious mononucleosis are found in the peripheral blood in a variety 



Fig. 11-3. Infectious mononucleosis, peripheral blood. Wright's stain, 

 (x 1700) 



of conditions (Table 11-1, Subgroup I-A) and observation which has been 

 recorded by a number of writers- 1T ie and even by McKinlay and Downey. 13 

 Figures 11-2 and 11-3 show cells in smears of two proved cases of infectious 

 mononucleosis. The cell shown in Figure 11-4 is from the peripheral blood 

 in a case of primary viral pneumonitis. The presence in the peripheral 



