OBSERVATIONS ON THE BLOOD OF GROUSE 313 



(acidophile) granules which stain deeply with eosin. The granules are often 

 rounded (Figs. 13-15); they vary in size, some eosinophiles containing large 

 granules (Fig. 13) which may be relatively fewer in number, while in other cases 

 the granules are small (Fig. 14), and may be relatively more numerous. Eosinophiles 

 with large granules a.re more prevalent. The contour of the granules is generally 

 round, but sometimes cells containing somewhat ovoid granules are seen which stain 

 intensely with eosin. 



Occasionally eosinophile cells are found in stained films, the granules of which 

 vary in shape within the same cell, some being round, some ovoid, and some almost 

 spindle-shaped. Such cells and their contained granules may be somewhat deformed 

 in the making of the film, otherwise it is difficult to classify these cells, which 

 are intermediate between crystalloid (polymorphonuclear) and granular eosinophiles. 



Mononuclear eosinophile cells are occasionally seen in the blood of normal 

 Grouse, and perhaps represent an early stage of development of the polymorpho- 

 nuclear eosinophiles. Such mononuclear cells are somewhat smaller than those 

 depicted in PL XLV., Figs. 13-15, and have round nuclei. They are rare, and 

 are perhaps analogous to the young eosinophile myelocytes of man. 



5. Mast Cells (coarsely granular basophile cells) are present in the blood of 

 normal Grouse (Figs. 16, 17). They are rare. The cells are more or less 



Mast cells. 



rounded, with a pale staining cytoplasm. The nucleus is usually rounded 



(Fig. 17) or slightly polymorphous (Fig. 16), and stains blue with Jenner's stain 



rather more deeply than similar cells in mammals. 



Basophile granules, which vary in size and in number, occur in the cytoplasm. 

 The granules are usually rounded and stain a deep purplish colour with Jenner's 

 stain in other words the granules are metachromatic. Mast cells measure from 

 y^ to IG'5^ in diameter. 



(c) Thrombocytes also occur in the blood of Grouse (Fig. 4). In the fresh 

 condition they suggest very narrow and slightly small erythrocytes. They xhrom- 

 are often elliptical, with an oval nucleus centrally placed. bocytes. 



When stained the cell-body is pale and vacuolated, suggesting a coarsely 

 reticular cytoplasm. The whole cell is basophile in its reactions, staining rather 

 faintly blue with Jenner's stain. 



Thrombocytes in Grouse average 9^ by 4^. 



These elements may collect in clumps, and show a marked tendency to 

 degeneration. 



