VITAL STAINING OF AMCEBOCYTE TISSUE. 295 



granules as well as in the case of the combination of eosin with 

 other constituents of the tissue. Even tissue killed through 

 previous heating behaves like living tissue as far as the giving off 

 of the stain is concerned, and both behave similar to filter paper 

 which has been stained with acid or basic dyes. On the other 

 hand, a .preceding treatment of the tissue with alkali or acid does 

 not alter the effect of the reaction of the surrounding fluid on the 

 decolorization of the tissue. 



So far as these experiments show, it seems then that the 

 staining of cell granules, and of other constituents of the cells 

 in amcebocytes, is of a similar character to the staining of cel- 

 lulose; the surrounding acid or alkali competes with the tissue 

 constituent or cellulose for the dye. The most probable assump- 

 tion which we can make is that the electrostatic forces of primary 

 or secondary valencies determine the fixation of the dye to the 

 tissue, and that acid and alkali compete with the tissue for the 

 alkaline or acid constituent of the dye. In addition it is very 

 probable that in certain cases acid and alkali influence the result 

 by converting the proteins into salts in which the protein con- 

 stituent becomes either kation or anion. 



While this statement applies as far as the test tube experiments 

 with stained tissue and the microscopic behavior of the cell 

 granules are concerned, it does not apply to the microscopic 

 behavior of the droplike structures in which neutral red is 

 deposited in granular as well as in hyaline cells. These drops 

 seem to a much greater extent to be independent of the reaction 

 of the surrounding medium. We saw that the stain remains 

 concentrated in these drops at a time when in neutral solutions 

 the majority of the granules have already lost their stain. We 

 saw furthermore that these drops remain intact for a relatively 

 long period of time in alkaline as well as in acid solutions, although 

 the latter bring about the almost instantaneous decoloration of 

 the granules. The droplike shape of these structures indicates 

 their liquid character; they represent therefore in all probability 

 solutions of neutral red. It is, however, possible that in addition 

 the dye is deposited also in solid form in certain cases. 



These droplike structures may remain preserved at least for 

 sometime, even after the cells have been destroyed, and thus they 

 may indicate the former situation of cells. We must therefore 



