OBSERVATIONS ON THE BLOOD OF GROUSE 311 



the cytoplasm of the members away from the periphery of the group is reduced 

 to a minimum. 



The lymphocytes are sometimes subdivided into large and small varieties. The 

 larger specimens of lymphocytes gradually merge into the small mononuclears, and 

 the naming and classifying of such leucocytes is often a matter of personal opinion. 



2. Large Mononuclear Leucocytes (Hyaline cells). These are large, approxi- 

 mately circular cells averaging 9//, to 11 '5^ in diameter (PI. XLV., Figs. 7, 8). 

 In a film stained with Giemsa's fluid the mononuclear leucocytes are easily Large 

 distinguishable, not only from their large size, but also from the fact "iear 

 that their cytoplasm stains a vivid blue and the nucleus a beautiful ' 

 purple. The general cytoplasm of the cell is almost homogeneous in character. 



The nucleus of a mononuclear leucocyte of Grouse is large, occupying about 

 half of the cell, and is often round or oval (Figs. 5, 6). At other times the nucleus 

 is somewhat curved or indented (Fig. 8). The chromatin of the nucleus takes the 

 form of a fairly dense mass, exhibiting in stained specimens a uniformly mottled 

 appearance ; it is situated to one side of the cell. 



With Jenner's stain the nucleus colours a rather deep blue, while the cytoplasm 

 stains only a faint blue and so is slightly basophile. 



As Burnett (1908, p. 35) writes: "One can find all stages between typical 

 lymphocytes with a small amount of strongly basophile, coarsely reticular cytoplasm, 

 and typical large mononuclears with a much larger amount of faintly basophile, 

 finely reticular cytoplasm." 



3. Polymorplionuclear leucocytes (Burnett) or Crystalloid eosinophile Cells 

 (Cullen, Warthin). The apparently polymorphonuclear leucocytes of 

 birds exhibit marked differences from those of mammals as regards phouuclear 



leucocytes. 



the contained granules. 



These cells in Grouse are round, as seen in stained preparations, and measure 

 from 9^ to 9 '5^ in diameter (Figs. 10-12). The nucleus consists of two or more lobes, 

 and varies in shape in other words, is polymorphous. The nucleus is fairly well 

 stained with Jenner's stain, and is coarsely reticular (Figs. 10-12). The cytoplasm 

 stains very faintly. 



Embedded in the general cytoplasm are a number of bodies or granules which 

 stain red with Jenner's stain and are oxyphilic. The bodies are generally described 

 as spindle-shaped with tapering ends, but their outline has also been compared 

 with that of a torpedo or cigar (Fig. 11). Other leucocytes are found with thinner 

 inclusions or "granules" which are rod-like in shape (Fig. 10). 



