THE CIRCULATING LIQUIDS OF THE BODY 29 



and differ also in other respects. They may be classified 

 <i) according to the presence or absence of granules in their 

 protoplasm, and the fineness or coarseness of the granules ; 

 (2) according to the chemical nature of the dyes with 

 which the granules stain. The most important recent 

 work on this subject is that of Kanthack and Hardy. They 

 find that Ehrlich's ' neutrophile ' cells are in reality oxyphile 

 that is, their granules do not stain with neutral dyes, 

 such as fuchsin or methyl green, but do stain with acid 

 dyes like eosin (Plate I., 2). They classify the wandering 

 cells of the blood into five varieties, as follows : 



((i) Coarselygranular(eosino- 

 phile cell of Ehrlich) - 10-11 u in diam. 

 (2) Finely granular ( neutro- 

 phile and amphophile cells 

 of Ehrlich) - - -8-9/1 



Basophile (granules stain- ( (3) Finely granular (tri-lobed 

 ing with methylene blue). ( nucleus) - - - - 7 P 



(4) Hyaline cells, free from 

 granules (one nucleus, 



generally spherical) - - 8'5-ioj* 



(5) Lymphocytes, possessing 

 a single large nucleus with 

 comparatively little proto- 

 plasm around it - 6 /i 



In human blood the finely granular oxyphile cells make 

 up 60 to So per cent, of the whole number of leucocytes, the 

 lymphocytes (and hyaline cells) 20 to 30 per cent., and the 

 coarsely granular oxyphile cells less than 5 per cent. ; but 

 these proportions are far from being constant. 



Blood-plates. When blood is examined immediately after 

 being shed, small colourless bodies (0*5 to 5 p in diameter) 

 of various shapes sometimes flat and of nearly circular 

 outline, sometimes irregular may be seen. These are the 

 blood-plates or platelets. They can be best studied when 

 the blood is run directly into some fixing solution.* Their 

 significance is unknown ; but they are not produced by the 

 breaking up of other elements of the shed blood, for they 

 have been observed within the freshly excised and therefore 

 still living capillaries in the mesentery of the guinea-pig 

 and rat (Osier). 



* Such as Hayem's solution (sodium chloride, i grm. ; sodium sulphate, 

 5 grm. ; mercuric chloride, o'5 grm. ; water, 200 grm.). 



