356 LEUKEMIA 



cially noted in 3 of my 41 cases. — Ed.] The phenomenon, however, which 

 especially characterizes leukocyte leukemia, and shows its origin to be the 

 changes in the bone-marrow {"myelogenous leukemia"), is that, besides the 

 polynuclear cells, their ancestors, the mononuclear granular leukocytes, i. e., 

 the neutrophilic and eosinophilic myelocytes, are always found in the blood 

 and occasionally are found in such great numbers (up to 100,000 per e.mm.) 

 as to simulate at first sight the blood picture of acute lymphemia with its 

 large mononuclear cells; some of the myelocytes show, as has already been 

 stated, coarse eosinophilic granules (eosinophilic myelocytes). The cells 

 which have been described, the polynuclear cells as well as the mononuclear, 

 are occasionally large, at other times remarkably small ("dwarf forms"). 

 Besides these immature leukocytes (the myelocytes), which normally are not 

 met with in the circulating blood, other immature forms of erythrocytes also 

 originating in the bone-marrow are found in the circulating blood stream of 

 patients with leukocyte leukemia, such as normoblasts and, more rarely, 

 megaloMasts in varying amounts, at times in great numbers. 



The enlargement of the spleen in this variety is especially well marked, 

 the enlargement of the lymph-glands is sometimes quite prominent, at other 

 times less so. [See editorial note on page 351. — Ed.] It is remarkable that 

 we rarely have an opportunity to observe the development of the tumors step 

 by step. Usually the physician sees the disease in its full intensity, so that 

 we must assume that leukocyte leukemia rapidly reaches the acme of its devel- 

 opment. Besides the splenic tumor and the enlargement of the glands, the 

 other clinical phenomena have already been fully described : The hemorrhagic 

 diathesis, the retinitis, the increase of uric acid in the urine, etc. 



Erom an etiological standpoint there is little of value in the diagnosis of 

 leukemia. In some cases leukemia appears to follow infectious diseases (ma- 

 laria, diphtheria, the puerperium, influenza, etc. ) , or occurs in connection with 

 trauma, as concussions (perhaps especially of the bones). These "causes" 

 of leukemia, considered as direct agents producing the disease, are of very 

 questionable nature. This, therefore, justified the sensation which followed 

 the "discovery" of Lowit (who had already distinguished himself by his 

 studies regarding the leukemic process) that the disease was due to the pres- 

 ence of amcebge in the blood and in the organs producing the blood cells. In 

 leukocyte leukemia Lowit found a form of ameba which he believed to increase 

 in the blood by sporulation (hsemamoeba leucffimiae magna) ; in lymphocyte 

 leukemia another form of parasite differing from the former by its active 

 motility (hsemamoeba leuc. parva vivax). Doubtless Lowit's discovery, if con- 

 firmed, would be of the greatest value in the explanation of the nature of leu- 

 kemia ; but, unfortunately, we cannot as yet reckon with this factor, as the 

 investigations are by no means concluded and have called forth many contra- 

 dictory opinions. [There are, I think, no contradictory opinions among those 

 who have studied Lowit's preparations, and repeated his technic. Competent 

 observers are unanimous in believing that Lowit's supposed parasites were, in 

 fact, artefacts. No competent investigator has confirmed Lowit's work. — Ed.] 



In the author's opinion, leukemia is due to a specific poison, which impairs 

 the process of blood formation, especially that of the white blood cells. In 



