416 SCIENCE PROGRESS. 



III. The finely granular oxyphil cell. 



IV. The coarsely granular oxyphil cell. 

 V. The finely granular basophil cell. 



VI. The coarsely granular basophil cell. 

 The following is a summary of the characters made out 

 for each of these several varieties. 



I. The Small Hyaline Cell. 



About the same size as a human red blood corpuscle, 

 this cell is often termed " lymphocyte " because so numerous 

 in lymphoid tissue, e.g., lymph glands, tonsils, etc. Its 

 scanty cell-substance appears quite devoid of granulation. 

 Its nucleus is spheroidal and deeply tingible. The cell 

 does not exhibit amoeboid movements, nor does it readily 

 adhere to surfaces as do many of the wandering cells. It 

 does not appear to have the power of ingesting particles, 

 and therefore cannot be included among "phagocytic" 

 cells. The birthplace of this cell lies undoubtedly in the 

 lymphoid tissues, probably in lymphoid tissue of all kinds ; 

 the production of it takes place especially at the " germ- 

 centres " of the lymphatic tissue where mitotic figures are 

 always abundant (3) ; and in the lymph issuing from the 

 active tissue young cells abound. The small hyaline leucocyte 

 is probably to be considered in all cases as a young cell — 

 an immature form. Into the blood it finds its way almost 

 entirely via thoracic duct. In the blood it is not the most 

 numerous form of leucocyte ; its numbers there are subject 

 to phasic variation, becoming highest two to three hours after 

 the ingestion of a full meal, and then forming even as much 

 as a third of all the wandering hsemic cells, and numbering 

 about 2500 lymphocytes in the cubic millimetre of blood. 

 In lymph from the thoracic duct it is much more numerous 

 absolutely as well as relatively to other leucocytes ; there 

 not uncommonly 25,000 lymphocytes per mm 3 of lymph 

 can be estimated, and they form more than 90 per 

 cent, of all the cells in the lymph. In "lymphatic leu- 

 kcemia," a diseased condition characterised anatomically by 

 enlargement of the lymphatic glands, the normal number 



