no THE TISSUES 



polynuclear form is derived from the polymorphonuclear by breaking 

 down of the connecting cords, leaving several separate nuclei or 

 nuclear segments. 



Granules in small numbers may be present in the protoplasm of 

 any of the leucocytes, but the protoplasm of about 70 per cent, of all 

 leucocytes is so distinctly and regularly granular that by some authors 

 a primary division into granular leucocytes and non-granular leuco- 

 cytes is made. Under this classification, lymphocytes and some 

 mononuclear leucocytes are placed in the non-granular group, while 

 transitional leucocytes, polymorphonuclear leucocytes and some 

 mononuclear leucocytes, are placed in the granular group. Aniline 

 dyes may be di\dded into acid, basic and neutral, according to 

 whether the coloring matter is an acid, a base, or a combination of an 

 acid and a base, and the granules of the granular leucocytes react 

 in a definite manner to these dyes, thus allowing the following 

 classificjttion : 



[ I neutrophile. 

 Granular leucocytes] 2 acidophile (eosinophile). 



[ 3 basophile. 



As the neutrophile granules are fine and the eosinophile granules 

 coarse, a classification of leucocytes into finely granular and coarsely 

 granular is sometimes made. 



1. Neutrophile Leucocytes. — These are the most numerous of all 

 leucocytes, making up about 68 per cent. Their protoplasm is 

 thickly studded with very fine granules which stain violet with a 

 mixture of eosin (acid) and toluidin blue (basic). Most neutrophiles 

 are polymorphonuclear, a few are transitional. They have a wide 

 distribution, being found not only in the blood itself, but in the 

 spleen and lymph nodes and as wandering cells in various tissues and 

 organs. 



2. Acidophile Leucocytes or, because the most common acid dye 

 used is eosin, eosinophile. The granules in these cells are coarse 

 and sharply defined. They stain strongly with acid dyes. Eosino- 

 philes are mainly polymorphonuclear, more rarely they are transi- 

 tional. They make up from i per cent, to 4 per cent, of all leuco- 

 cytes. In certain pathological conditions their number is greatly 

 increased. 



3. Basophile Leucocytes.— ThQ granules in these cells are rather 

 coarse and irregular in shape and are distributed unevenly through 



