AMOEBAE VERSUS TISSUE CELLS 5 



to the tissue culture. The fibroblasts responded at once in the 

 usual way (W. H. Lewis, '19) to this stain. ]\Iany of the vacuoles 

 stained pink with one or more purple granules. The vacuoles 

 were grouped around the nucleus and centriole, just like the 

 neutral-red granules. This same solution applied to the amoebae 

 stained the cytoplasm a pale blue, the granules a purple blue, 

 and the karyosome of the nucleus a purple blue with a clear 

 area in the center. The nucleus with its karyosome and clear 

 area were pulled away from the endoplasm out into the ecto- 

 plasm. The amoeba moved slowly and sent out many large 

 clear pseudopodia, a kind of lunging movement similar to blebs 

 in tissue cells. Within half an hour the granular endoplasm had 

 contracted into a solid blue mass of irregular shape, the nucleus 

 remaining in the ectoplasm. Motion had stopped and the 

 amoeba was dead. 



This solution of brilliant cresyl blue was diluted one-half with 

 Locke solution and applied to the amoebae. This time about 

 half of the endoplasmic granules took the deep blue stain, the 

 other half remained unstained and were quite refractile. The 

 karyosome stained purple as before, but with a bluish purple 

 area around it and the cytoplasm was a pale blue. The amoebae 

 moved actively, but in a short time the granules lost their color 

 and the nucleus and cytoplasm stained more deeply and the 

 amoebae were dead. 



When the solution was again diluted one-half and added to a 

 new hanging drop of amoebae, the effect was the same as that on 

 the tissue cells with a solution four times its strength. The 

 nucleus was not stained. The endoplasm contained purple 

 granules as well as the pink vacuoles with their purple granules. 

 The amoebae moved rapidly and progressed normally. 



Methylene blue 



The solution of methylene blue, when added to the tissue cells, 

 did not stain the nucleus nor cytoplasm. The vacuoles stained 

 blue and the one or more granules within them took a deep blue 

 stain. Blebs were forming on many of the cells. The same 

 solution added to the amoebae stained the karyosome a deep 



