82 RHODA ERDMANN 



interpretation of the changes observed in the different types. 

 Some exact knowledge could be acquired only by comparing 

 and combining the phenomena observed in bone-marrow cells 

 in preserved and stained preparations after they had been in 

 the plasma medium for, well defined periods. 



In figure 7, an exact microscopic field of a bone marrow prep- 

 aration, after 36 hours incubation, is shown. The implanted 

 tissue particle would be (if shown on the drawing) on the left 

 side of the preparation. The cells shown have migrated to the 

 zone next to the implanted bone-marrow tissue particle which- 

 was taken from a full-grown chicken and contained fat 



Eosinophil leucocytes in various developmental stages are 

 numerous. They are in rapid amoeboid movement, and by 

 continued fragmentation diminish in size and multiply in 

 number. Their plasma is slightly basophil. The nuclei are 

 strongly chromophil and the nuclear leucocytic structure in 

 most forms is indistinctly developed. By comparing the nuclear 

 structure wdth that of eosinophil leucocytes which have been 

 24 hours in cultivation (fig. 9) we can better distinguish the 

 typical leucocytic network of chromatin particles and threads. 

 The plasma of these leucocytes and of those figured in figure 8, 

 which have been only one hour in the plasma medium, is acido- 

 phil and the round granulations are very distinctly recognizable. 



Besides the changes in the cytoplasm of the leucocytes from 

 acidophily to basiphily, other phenomena are noticeable. After 

 one hour and still more after 36 hours incubation, the leucocytes 

 of all sizes are losing and expelling the granulations. The nuclei 

 of these forms have either become pale and indistinct (fig. 7, 

 right side, below) or condensed and strongly chromatic (figs. 

 12 to 14). They may fade out to mere shadows and disappear. 



The farther the polymorphonuclear eosinophil leucocyte ad- 

 vances into the plasma clot, the more its cytoplasm spreads 

 out in the tissue culture. The granulations in consequence no 

 longer appear lying closely together, but seem widely scattered 

 in the cytoplasm. The leucocytes finally lose their power of 

 cytoplasmic division. This happens generally on the margin 

 of the plasma clot where the culture medium is thinly spread. 

 The horseshoe — or kidney-shaped nuclei separate, become 



