LEUKEMIA OR LEUKOCYTHJEMIA. 315 



The spleno-medullary variety of leukaemia is especially recog- 

 nized by the presence in the blood of numbers of large-sized 

 leukocytes, which have been called myelocytes on account of 

 their supposed origin in bone-marrow. These cells are rarely 

 if ever seen in normal blood ; they are usually 1 Q/JL to 20/j in 

 diameter, though occasionally not much larger than a red 

 corpuscle, when they can only be distinguished from the 

 mononuclear leukocytes by the presence of neutrophilic gran- 

 ules in their protoplasm, or sometimes of eosinophilic granules 

 eosinophile myelocytes. When the blood is stained with 

 haematoxylin and eosin these neutrophilic granules cannot be 

 seen ; but if Ehrlich's triple stain is employed they are readily 

 recognized. In this variety of leukaemia the myelocytes often 

 make up 30 to 50 per cent, of the total number of leuko- 

 cytes, while in other diseases in which they rarely occur they 

 never exceed 2 to 9 per cent. 



The relative number of eosinophiles normally constituting 

 2 to 4 per cent, of the white blood-cells is not usually in- 

 creased, though there is always an absolute increase in their 

 number 50 to 80 per cent, of which are eosinophile mye- 

 locytes. It was formerly supposed that a relative increase 

 in the eosinophiles was diagnostic of leukaemia ; they are in- 

 creased to a much greater extent, however, in some other 

 affections notably in asthma and diseases of the skin and 

 often are even diminished in leukaemia. The number of poly- 

 nuclear neutrophiles is relatively diminished, making up but 50 

 per cent. in some cases even less than 10 per cent, of the total 

 number of white blood-cells ; an increase would suggest some 

 inflammatory complication. The small lymphocytes are also 

 relatively reduced in number, constituting but 3 to 5 per cent., 

 instead of 15 to 25 per cent, of the total number of leukocytes. 



Basophilic myelocytes and small leukocytes are occasionally 

 noted, their protoplasm containing granules which have a 

 selective affinity for basic dyes. 



The red blood-corpuscles are usually reduced to two or three 

 million per cubic millimetre, and proportionally likewise 

 the haemoglobin. Alterations in the size, shape, and stain- 

 ing properties of the red cells may be noted ; and erythro- 

 blasts are always found at some stage of the disease 

 mostly normoblasts, though some megaloblasts and micro- 



