70 RHODA ERDMANN 



properties of the plasma, are transformed into the cell culture 

 type (p. 56). This cell culture type (see his fig. 2, pi. 3, and his 

 fig. 3, pi. 4) represents small polymorphonuclear leucocytes 

 (p. 49) which have undergone the transformation, but not only 

 does the cell culture type originate from lymphocyte forms, but 

 this 'stem cell' can also be transformed through the transition 

 stage of amoeboid forms into 'giant cells,' syncytia, and, as said 

 before, into the cell culture type (table 1, p. 56). 



Thus it is clear that, according to this author's view, all the 

 different forms described by Foot in 1912 and 1913 originate 

 from the microlymphocytes. Until the present time ('16) this 

 important fact lacked verification, but by the cultivation of the 

 virus of cyanolophia in chicken bone marrow an opportunity 

 was afforded of observing the changes which Foot describes. A 

 careful study of the morphological and cytological characters 

 of the cells figured in the above mentioned papers, soon showed 

 a lack of transition stages, which are needed as proof of Foot's 

 final theory. Further, the nuclei of cell forms which are said 

 to be transformed into each other do not show close resem- 

 blances, e.g., the cells in figures 1 and 3, 1913, which are said to 

 be eosinophil leucocytes at different stages of incubation, have 

 different nuclear structure as well from each other and from 

 the cell of the cell culture type (fig. 2, left side, 1913). The 

 nuclear structure of this particular cell (fig. 2, left side, 1913), 

 however, has a certain resemblance to the nuclei shown in 1912, 

 figures 5 and 6. These cells are considered by Foot as stages 

 connecting the ' Riesenzellen' with "eine Art von monnuklearen 

 basophilen Zellen" (1912, p. 450). But here, as far as could 

 be judged from the draA\ings, the cytoplasm of the cells in 

 figures 5 and 6 is very different. Figure 5 has granules, figure 

 6 does not show them; only traces of digested nuclei of other 

 cells are visible. These contradictory facts present a priori 

 difficulties in accepting the views of Foot. But they appeared 

 far more disconcerting on examining the cells themselves. 



