LEUCH^MIA LEUCOCYTH.EMIA. 757 



are due to an increased formation of cellular elements, and not to tlieir 

 retention, as we thought was probable in the other forms of enlarged 

 spleen and lymph glands. It is a question whether the cells, so plen- 

 tifully formed in the spleen and lymphatic glands during leuchaemia, 

 differ in any way from those formed under normal circumstances. If 

 we could suppose that only the white corpuscles of the blood origi- 

 nated from the colorless cells of the lymph and spleen pulp, leuchaemia 

 might be regarded as a simple hyperplasia. Although the transfor- 

 mation has not been directly observed, still it cannot be doubted that, 

 under normal circumstances, the red corpuscles also originate from the 

 colorless lymph-corpuscles, and from colorless cells of the spleen-pulp ; 

 hence, in explaining leuchaemia, where this transformation is much 

 limited, we must suppose that the numerously-formed cells do not 

 possess the power of becoming red blood-corpuscles. 



In certain case's of this disease, described by Virchow, Friedreich, 

 and ditcher, other oigans also, as the liver, kidneys, intestinal mu- 

 cous membrane, and pleura, produced lymphatic elements at circum- 

 scribed spots ; so that, as Virchow says, in these cases there was not 

 only a lymphatic dyscrasia, but at the same tune a lymphatic dia- 

 thesis. 



The etiology of leuchaemia is entirely obscure. The disease is met 

 with in both sexes, but more frequently in males than in females ; it is 

 very rare in childhood. Most cases recorded have affected persons of 

 middle age. No connection has been proved between this disease 

 and malarial infection, or scrofula. In a few cases the disease ap- 

 peared to have a certain relation to menstruation and to the puerperal 

 state. 



ANATOMICAL APPEABANCES. While, in normal blood, there are 

 about three hundred and fifty red blood-corpuscles to one white one, 

 in leuchaemia the number of white corpuscles may become so much in- 

 creased, and that of the red ones so much diminished, that the former 

 will become a sixth or even half as many as the latter. In the splenic 

 form of the disease the white blood-corpuscles are not distinguishable 

 from those of normal blood ; they are distinct, well-developed cells. 

 In the lymphatic form, on the other hand, Virchow and other observ- 

 ers found numerous free nuclei and small cells, both of which corre- 

 sponded exactly with the elements found in the lymphatic glands. If 

 the spleen and lymphatic glands were diseased at the same time, if 

 the spleen-disease prevailed, there were more of the larger, cellular ele- 

 ments in the blood ; on the other hand, the more extensive the dis- 

 ease of the glands, the more numerous were the small lymphatic ele- 

 ments. Examinations of leuchaemic blood have shown that its specific 

 gravity is much less than that of normal blood : while the latter may be 



