Wlien the nucleus stains darkly, the overlying 

 magenta bodies that have the same staining af- 

 finities are not clearly visible (figs. 104 and 109) . 

 When the nucleus is extensively lysed as in fig- 

 ures 105-107 the overlying magenta bodies are 

 usually conspicuous. 



No one has yet associated the presence of ma- 

 genta bodies with any particular pathological 

 condition in birds, but the impression has been 

 gained that they are often associated with birds 

 that have a disposition toward early mortalhy. 

 Olson (1952) noted them in lymphocytes taken 

 from cases of avian leukosis but he does not say 

 that they are specifically associated with the dis- 

 ease. There is much speculation concerning the 

 presence of a lymphomatosis agent of viral size 

 that, by acting upon the lymphocyte, ultimately 

 stimulates the cell into a neoplastic condition. 

 These magenta bodies may have no relationship 

 to lymphomatosis infection but their sporadic ap- 

 pearance in lymphocytes of chickens would seem 

 to justify further study in an effort to find out 

 what they are and what they are doing in the cell. 

 Their presence does not necessarily indicate a 

 dying cell; mitosis can occur (fig. 108). 



Michaelis and Wolfe (1902) are said by Doan 

 (1932) to be the first to describe azurophilic 

 granules in lymphocytes. They used blood from 

 man. Their description agrees closely with the 

 observations made on avian blood. They estab- 

 lished the fact that it was actually a lymphocyte 

 that contained the granules. In circulating 

 blood about one-third of the lymphocytes con- 

 tained these granules, but they were absent from 

 the lymphocytes of lymph nodes. The signifi- 

 cance of these granules is still not adequately 

 established. 



Another type of cell response that produces 

 atypical lymphocytes is hypertrophy with vacu- 

 olization of the cytoplasm (figs. 109-112). The 

 stain taken by the cytoplasm is faint compared 

 with that of the typical normal lymphocyte. The 

 vacuoles may be small as in figure 109, irregular 

 in size as in figure 111, and large as in figure 112. 

 There may be few or many magenta bodies and 

 these may show considerable variation in size; 

 they may lie either in the vacuoles or between 

 them or at their margin. From the appearance 

 of the cytoplasm in which many vacuoles are 

 present, a transformation toward a macrophage 

 might be suggested. The nuclei of such vacu- 

 olated cells as seen in figures 109-112 show a 



closer resemblance to those of lymphocytes than 

 to those of macrophages. The nucleus of the 

 macrophage was studied in blood spots (Lucas, 

 1946) and in cardiac punctures of the embryo 

 (figs. 309-317) where the typical chromatin pat- 

 tern was a uniform reticulum with evenly dis- 

 tributed, dotlike bodies of chromatin at the inter- 

 stices of tlie network. This punctate appear- 

 ance of the macrophage nucleus is quite different 

 from the delicate reticulum or massive irregular 

 clumps of the typical lymphocyte. 



Downey and McKinlay (1923), and Blackfan, 

 Diamond and Leister (1944) illustrated and de- 

 scribed the lymphocytes found in cases of in- 

 fectious mononucleosis. The azurophilic bodies 

 and the vacuolated cytoplasm of human lympho- 

 cytes in infectious mononucleosis simulate, in 

 part, the magenta bodies and hypertrophied, 

 vacuolated cytoplasm of avian lymphocytes, 

 which may be seen in some seemingly normal 

 birds. Although chickens do not carry the vims 

 of infectious mononucleosis, as far as we know, 

 the fact should not be ignored that lymphomatosis 

 is also an infectious disease, and that it has a stim- 

 ulating effect on the mononuclear cells accumulat- 

 ing within the tissues of the avian body (Lucas, 

 1949; Lucas, Craig, and Oakberg, 1949; Lucas 

 and Oakberg, 1950; Lucas, Denington, Cottral 

 and Burmester, 1954; Oakberg, 1949, 1951). 



Osgood (1935) described fenestration in lym- 

 phocytes from cases of mononucleosis. He ob- 

 served a vacuolization and canaliculization of 

 the nucleus somewhat similar to, yet different 

 from, the clefts of nuclei of avian cells. 



A further variant of the magenta bodies is 

 shown in figures 113-116, in which the colors 

 range from a pale orange to the typical magenta 

 color. Some of these cells show the slight nu- 

 clear lysis that already has been mentioned as 

 occurring in lymphocytes with magenta bodies. 

 The cytoplasmic inclusions in figure 114 show 

 gradation from the light to the dark type of 

 granule but the direction in which the reaction 

 is going is not known. Cells of this type are 

 rare and it should be noted that these cells came 

 from birds having the same parents. In these 

 same slides monocytes were present that seemed 

 to have an unusually large quantity of azuro- 

 philic granules. The history of this family of 

 nine birds is interesting. All were hatched June 

 19, 1944. The blood smears were taken at 112 

 days of age, except from F205C5. 



64 



