THE BLOOD AND THE BLOOD-FORMING ORGANS. 389 



nodes as a rule, and a moderate increase in the size of the spleen and 

 liyer. Cases are on record, however, in which there was no enlargement 

 of the spleen or lymph -nodes. ' The blood changes are very character- 

 istic. The red_cells dimmish rapidly in mrmbers, normoblasts are pres- 

 ent, and the leucocytes~are increased though usually belpw~H)0 1 000. The 

 forms present are chiefly lymphocytes, either large or small, the large as 

 a rule predominating. The bone mawwv-is. altered to a tissue showing 

 large numbers of lymphocytes, the so-called 1 ymphoid hyperplasia, which 

 often extends to the lymphoid tissue in the viscera. 



Chronic Lymphatic Leukaemia. The blood shows a jgyere anaemia with 

 great increase in the lymphocytes. The small forms of the lymphocytes 

 are most abundant, in contradistinction to the acute type of the disease 

 in which the large forms are usually in excess. The lyjnph-nodes and 

 spleen are usually enlarged ; the bone marrow is in a condition of lym- 

 phoid hyperplasia, and there are lymphoid infiltrations in the various 

 organs (see Plate II., Fig. 5). 



Chronic Myelogenous Leukaemia. The blood shows a severe anaemia, 

 rarely of a pernicious type, with marked quantitative and qualitative 

 changes in the leucocytes. The increase in number of white cells may 

 be to more than one million per cubic millimetre. Myelocytes^ both 

 ueut rophilTc~aud eosiuophllic, are quite coustantTy^reseiit in considerable 

 numbers. They may form a large proportion of the leucocytes present. 

 Basophile cells are very abundant in cases of long duration, especially 

 the type with polymorphic nuclei, myelocytes with basophilic granula- 

 tions being rare. Iii_rapidly_aiiyai i ciug..cases mitoses may be rarely seen 



in the red cells and in the leucocytes (see Plate II., Fig. 5). 







The pathological forms of leucocytes in myelogenous and lymphatic 

 leukaemias have little or no amosboid motion. This explains the inter- 

 esting fact that the pus from an abscess in a leukaemic subject contains 

 only the polyuuclear neutrophile cells found in such exudates in persons 

 with a normal blood condition. In acute infections also, the number of 

 myelocytes present in the circulation may be greatly reduced and the 

 blood may even lose the cell forms characteristic of leukaemia, the myelo- 

 cytes being replaced by the ordinary polynuclear leucocytes of normal 

 type. 



The same condition maybe seen in mild cases, which may under treat- 

 ment reach a point in which it is difficult to make a diagnosis from the 

 blood alone. 



In this connection, it must be remembered that the blood picture in 

 pernicious anaemia and the leukaemias is a very variable one. As a rule, 

 more than one examination is necessary for a certain diagnosis, and it 

 must not be forgotten that occasionally a case, apparently of pernicious 

 anaemia, may go on to a typical lymphatic or myelogenous leukaemia. 



In myelogeuous leukaemia there is hyperplasia of the bone marrow, 



1 See Kelley, University o Pennsylvania Medical Bulletin, 1903, p. 270. 



