2Q6 LEO LOEB AND KENNETH C. BLANCHARD. 



assume that there must be some factor which prevents these 

 drops from mixing with the surrounding fluid. Two possibilities 

 exist in this respect : either they are surrounded by a protein mem- 

 brane, or, they consist essentially of lipoid material in which the 

 stain is dissolved. 



However that may be, we may conclude that when dissolved in 

 droplike structures the neutral red remains preserved at a time 

 when the neutral red which stains the granules has become dis- 

 sociated from the latter. We may furthermore conclude that 

 stained granules do not, as has been assumed, represent solutions 

 of neutral red, and that neutral red may therefore be present in 

 the cells in at least two forms, namely, (i) in a chemical com- 

 bination with the granules, or, (2) in solution in the clroplike 

 structures, and that thus the conditions in which the neutral red is 

 deposited in these two cases differ one from another. It may be 

 suggested that the second mode of deposition of neutral red, 

 namely, that in droplet form, is similar to the storage of acid 

 vital stains, like trypanblue and pyrrholblue, which occurs in 

 certain tissues. 11 



SUMMARY. 



1. Neutral red, as a representative of the basic dyes, stains the 

 granules of the amcebocytes. The stained granules lose their 

 stain gradually in neutral and almost immediately in acid solu- 

 tions. Alkaline solutions intensify the staining. 



2. In addition to the granules, droplike structures in the 

 amoebocytes are stained with neutral red. The latter are very 

 much more resistant to decoloration than the granules. They do 

 not give off spontaneously the stain as readily as do the granules, 

 nor are they as readily decolorized under the influence of acid as 

 are the latter. 



3. The effect of acid and alkali on the neutral red stain in 

 amcebocytes can be demonstrated not only in single cells micro- 

 scopically, but also in the test tube if we use amoebocyte tissue 

 previously stained with basic or acid stains. Acids cause the 

 giving off of basic dyes, and alkali causes the loss of acid dyes 

 which had previously combined with the tissue. This relation 

 prevails notwithstanding the fact that acid and basic dyes stain 



11 H. M. Evans and W. Schulemann, D. med. Woch., 1914, XL., 1508. 



