14 TISSUES AND ORGANS 



due to the application of the name to other elements that possess 

 some similar characters. 



It is quite common to find, in the blood, even of normal humans, 

 a small number of cells with intensely basophilic cytoplasm in 

 which the nucleus is not excentric. These are the so-called 

 irritation cells of Tiirk, and seem to be stages in the development 

 of the true plasma cell, so that there is perhaps no very great 

 objection to classifying both forms together. Difficulties arise, 

 however, in some cases of leukaemia in which cells with intenselv 

 basophilic cytoplasm are present in the peripheral blood. These 

 elements usually present signs of very definite immaturity, e.g., 

 nucleoli are distinctly visible. Those who regard lymphocytes as 

 being derived from a specific stem-cell, the lymphoblast, contend 

 that some of these elements may justifiably be called lympho- 

 blastic plasma cells. It is also well known that almost any cell 

 with non-granular cytoplasm may, in abnormal circumstances, 

 show excessive basophilia of its body ; so we read of myeloblastic, 

 monocytic and even erythroblastic plasma cells. In view of the 

 uncertainty of the whole nomenclature it is indubitably best to 

 describe these cells in detail, or, if a name must be used, to state 

 definitely to which category one wishes to refer them ; the simple 

 name " plasma cell " is far too ambiguous to be employed without 

 due qualification. 



The function of the lymphocytic plasma cell is unknown, but 

 histological examination of carcinomata suggests that they may 

 play a part in absorbing and disposing of products of tissue 

 metabolism ; certainly they are often very numerous in the 

 stroma of epithelial malignant tumours where presumably intense 

 katabolic processes are present. 



Myeloblasts. It has already been said that the vexed question 

 of the origin of blood cells will not be considered here in any 

 detail, but some reference must be made to the non-granular 

 leucocyte with an immature form of nucleus so often seen in the 

 blood in acute leukaemias. It must be presumed that the reader 

 is acquainted with the usual descriptions of these cells, so that we 

 can pass directly to an account of their characters as determined 

 by the method of supra-vital staining with neutral red and Janus 



