346 LEUKEMIA 



tiate two principal varieties, mononuclear and polynuclear (or polymorpho- 

 nuclear) cells, both of which show various subvarieties : 



A. Mononuclear Forms: Cells with one nucleus and varying amounts 

 of basophilic, non-granular protoplasm. 



1. Lymphocytes, characterized by a large, round, centrally-placed nucleus 

 and a narrow protoplasmic ring. The latter, as well as the nucleus, reacts 

 lasophilically, especially the protoplasm which shows no granulations. [No 

 granulations, that is, with Ehrlich's stain. With the Eomanowsky stain a 

 variety of pink, violet, and sometimes a few blue granules are seen in the 

 protoplasm of the lymphocytes. This is true of all sizes of lymphocytes, 

 though commoner in the large forms. — Ed.] The lymphocytes have no power 

 of ameboid movement. [I am convinced by the observations of several com- 

 petent men that lymphocytes (especially, but not only, the larger forms) do 

 have the power of ameboid movement. — Ed.] The majority of them scarcely 

 attain the size of the red blood discs ; rarely are large lymphocytes found, espe- 

 cially in the blood of children. The number of lymphocytes amounts to about 

 25 per cent, of the white blood-corpuscles. Some individual examples, espe- 

 cially of the larger forms, show slight segmentation of protoplasm. 2. Large 

 mononuclear leukocytes, twice or three times larger than the lymphocytes, 

 differing markedly from the large lymphocytes, in that the large, usually oval 

 nucleus is generally eccentrically situated and that the non-granulated proto- 

 plasm is relatively well developed. This protoplasm and the nucleus have, 

 like the lymphocytes, a basophilic reaction, but, in contrast to the latter, the 

 protoplasm stains less readily than the nucleus. Transitional forms between 

 the first and second variety are not observed, and for this reason, according 

 to Ehrlich, the " large mononuclear " cells are strictly differentiated from the 

 lymphocytes, all the more so as " transitional forms " from the large mono- 

 nuclear to the polynuclear are observed, i. e., large cells with neutrophilic 

 granulation and with indentations in the nucleus. [All recent and unpreju- 

 diced observers seem to me to agree that there are abundant transitional forms 

 between the " large lymphocyte " as here described and the " large mononu- 

 clear leukocyte " of the same text. A differentiation of these two varieties is 

 in my opinion impossible. — Ed.] The number of the large mononuclears in 

 normal blood is always small (about one per cent.). 



B. Polynuclear Forms : Cells with several small nuclei or usually with 

 a polymorphous nucleus, i. e., with marked indentations of the nucleus, so that 

 some of the nuclear segments are connected by thin chromatin threads. The 

 polymorphonuclear ("polynuclear") leukocytes are further characterized by 

 ameioid movement. The protoplasm is granular and shows varying condi- 

 tions regarding staining which give rise to the differentiation into the three 

 following varieties: 



1. Neutrophilic polynuclear leukocytes, usually designated as "polynu- 

 clears," characterized by the dense granulation of the protoplasm and the 

 affinity of the same to " neutral " staining material. They form in the nor- 

 mal blood about 70 per cent, of the white blood-corpuscles. [There are no 

 true neutral stains. A special differential acid stain like Ehrlich's " triacid " 

 is what is here referred to. 



