975 



more conspicuous in a preparation from a liilten of 8 da^s. Here 

 a slight alteration in the appearance can also be noted. Whereas 

 the giant-cells were on the first day comparatively quiescent and 

 the compound nuclei formed beautiful rings and horseshoes, on the 

 8^'i day a general mobility is discernible. The number of giant-cells 

 is, indeed, about as large as before, but the nuclei present fewer 

 ring- and horseshoe-shapes and stain rather more deeply than their 

 surroundings. This statement does not apply to every individual 

 cell. Likewise the cytoplasm often stains more intensely wilh eosin. 



Fig. 2. Spleen of cat, 1 week. ZENKER-Ironhematoxylin- 

 eosin, 950 X natural size. 

 a. megakaryocyte in a mitotic stage, b. wall of a vein. 



One single mitosis is also noteworthy. (Fig. 2). Here the cell-body 

 is stained more basophilic and granular. In a sjmilar preparation 

 of a kitten of two weeks I was struck, on cursory inspection, by 

 the location of a giant-cell in a large vein. (Fig. 1). This discovery 

 gives a cine to the whole process as in nearly every large vein 

 appeared several cells similarly disposed. It also soon became clear 

 how they got there, when I encountered cells protruding crosswise 

 through the vessel-wall (Fig. 3 a and b). On closer investigation the 

 following process can be deduced from the various preparations: A 

 giant-cell displaying great amoeboid activity (Schridde 1905; sends out, 

 when about to vanish, pseudopods in all directions, which process 

 is attended with all the typical features of degeneration. The nucleus 

 shrinks, gets rounded, presents no longer a distinct appearance, gets 

 much more deeply stained, in a word : pyknotic. The protoplasm of this 

 cell-body at first stains slightly deeper with eosin, rather bi'ownish, 

 but in a more developed stage even the cytoplasm is no longer stainable, 

 only the blurred periphery being visible. (Fig. 4 c and (/). The 

 cytoplasm of the cell now protrudes through the vessel-wall either 



68* 



