180 PHYSIOLOGY. 



three groups, the basis of classification depending upon the staining 

 proclivities of the granules held within the cytoplasm. To the first 

 group he gave the name eosinopliiles, because the granules of this 

 class of corpuscles stain best with acid aniline dyes. The basophiles 

 comprise the second group and include those staining best with basic 

 dyes. Last come the neutropliiles; their granules are capable of 

 being colored only by the presence of neutral dyes. This classifica- 

 tion is a very popular one, and holds a very prominent position in 

 pathological circles. 



White blood-corpuscles are classified in two varieties: 



I. Lymphocytes are without granules in the cell and without 

 amoeboid movement. 



(a) Small mononuclear lymphocytes are about the size of a red 

 blood-corpuscle, have a large, round, concentric nucleus, a 

 small amount of cytoplasm, and are strongly basophilic, 20 

 per cent. 



(b) Large mononuclear lymphocytes have a large, oval nucleus, 

 located excentrically ; cytoplasm relatively considerable, not 

 granular, and are weakly basophilic, 1 per cent. 



II. Leucocytes have a granular cytoplasm and amoeboid move- 

 ment. 



(a) Transitional are mononuclear leucocytes, having a large 

 nucleus, considerable granular cytoplasm, and neutrophilic 

 granules. They are a transitional form between the largo 

 lymphocytes and the polymorphonuclear leucocytes, 7 per 

 cent. 



(b) Polymorphonuclear leucocytes have the amoeboid movement 

 well developed; the granules in the cytoplasm are neutro- 

 philic; and the nucleus is divided into lobes, connected by 

 bands, 70 per cent. 



(c) Eosinophiles have a segmented nucleus, the granules in the 

 cytoplasm are large and stain with eosin ; they are oxyphilic, 

 2 per cent. 



(d) Mast cells are small in number, with a polymorphic nucleus 

 and basophilic granules, 0.1/2 per cent. 



Amoeboid Movement. All the leucocytes have in common a very 

 remarkable attribute of spontaneously changing their shape and 

 thereby executing certain movements, which, from their great 

 similarity to those performed by the micro-organism, amoeba, have 

 been termed amoeboid. When the conditions of temperature and 

 moisture are maintained at the proper standard, the leucocytes will 



