426 SCIENCE PROGRESS. 



period of amoeboid and vagrant existence they can settle 

 down once more as fixed corpuscles, and produce the fibres 

 and the variously complicated matrix of dense connective 

 tissue, e.g., in the repair of wounds. As a possibility this 

 view is tenable, but it has been shown not to hold good in 

 all the instances in which the sequence of events has been 

 examined carefully (21). 



That the coarsely granular basophil leucocyte and the 

 two forms of oxyphil leucocytes must all three be con- 

 sidered specifically different individuals there is little reason 

 to doubt. Whether the two forms of hyaline leucocyte are 

 not stages of the same cell, and whether one of them or 

 both may not be young forms of the finely granular, are 

 possibilities that seem not improbable. Apart from the 

 not very numerous coarsely granular oxyphil leucocytes 

 and the much rarer finely granular basophil, the leucocytes 

 of the blood have been classed by Ouskow (22) and 

 Khetagorow (23) as (1) young elements, (2) ripe elements, 

 (3) over-ripe elements. Among the young elements they 

 place the small hyaline cells (lymphocytes) and some 

 hyaline forms not much larger than lymphocytes. By ripe 

 elements they mean the large hyaline forms and certain 

 others transitional in appearance between those and the 

 finely granular oxyphil ; these last are their over-ripe ele- 

 ments. They believe the lymphocytes enter the blood 

 from the lymph glands and from the spleen, and the some- 

 what larger hyaline form from the red marrow. These 

 views are at present, however, conjectural rather than 

 based on any actual demonstration. 



As to the life history of the coarsely granular oxyphil 

 cell there is a small element met with in serous fluid and 

 blood which is probably the young form of this cell. It 

 has a spherical nucleus and a scanty amount of cell-sub- 

 stance containing a few granules of the typical appearance 

 and reaction. Similarly it is fairly easy to trace the in- 

 dividual growth of the coarsely granular basophil cell from 

 a small cell somewhat like a lymphocyte, except that its 

 scanty cell-substance contains the characteristic basophil 

 granulation ; every intermediate form up to the large "mast 



