160 The Lymphocyte and Lymphocytic Tissue 



with cells that may be large or small, mononuclear or multinuclear, and 

 that may or may not be associated with the lesions of leukemia or Hodg- 

 kin's disease. In relation to the present discussion, it is probable that some 

 of the tumors with cells of uniform size only slightly larger than lympho- 

 cytes may be composed of lymphoblasts 4 ' J - or of primitive lymphoid cells 

 (reticular lymphoblasts). 



6. In general, the kind of cell and type of manifestation (focal or diffuse) 

 tend to remain the same throughout the course of the disease. 



Exceptions: The exceptions are numerous- but are of limited kinds. 

 Changes from a localized to a generalized form of disease or from a chronic 

 to an acute type are not fundamental changes in kind, but in manifestation. 



Changes in cell type, for example from reticulum cell to lymphocyte or 

 vice versa, are theoretically possible but are certainly exceptional. The 

 possibility of the coexistence of two neoplasms (e.g., reticulum cell sarcoma 

 and lymphocytic leukemia 1 ') makes the interpretation of such cases on the 

 basis of "change of cell type" difficult. On the other hand, changes within 

 the concept of "Hodgkin's disease" (e.g., change from Hodgkin's para- 

 granuloma to granuloma to sarcoma) are not changes of kind, inasmuch 

 as involvement of the same cell or origin (reticulum cell, histiocyte) is the 

 basic lesion in all. 



LEUKEMIA IN MICE 



A study of leukemia in mice provides information on a few points relative 

 to this discussion. 



1 . The blood picture and distribution of lesions of mouse leukemia trans- 

 mitted by cell implants are not necessarily the same as in the original donor 

 mouse, 1 " indicating that these features do not indicate differences in kind. 



2. Changes in the distribution of lesions in transplanted leukemia may 

 be affected by experimental procedures, 8 indicating that different mani- 

 festations of the disease are dependent in part on the relationship obtaining 

 between the transplanted cells and the host. 



3. Changes in acuity of the disease during a series of transmissions may 

 be preceded by changes in cell morphology. 7 



SUMMARY 



These observations indicate that study of the peripheral blood or of 

 an excised lymph node does not alone enable one to determine the distribu- 

 tion of lesions or the rapidity of their course. The importance of supple- 

 mentary information is clearly expressed by Boyd: "It is therefore of the 



