The vital staining of normal and malignant cells. III. Vital staining of acinar cells of the pancreas and its bearing on the theories of vital staining with basic dyes

Is there a fundamental difference between vital staining with acid, and with basic dyes ? Upon the answer to this question depend some of the most controversial problems which are occupying the minds of cytologists at the present time. I have endeavoured to contribute towards the solution of this problem by a study of the acinar cells of the pancreas of the mouse. The pancreas cell offers considerable advantages for such a study, owing to the ease with which its cytoplasmic structure can be demonstrated, and its ready stainability with basic dyes. Furthermore, this cell has received much attention from those interested in the cytology of secretion and its relation to vital staining. 2.Theories of Vital Staining with Basic Dyes . In previous communications (Ludford, 1928, 1929) I have discussed the present position of our knowledge of the cellular mechanism involved in vital staining with acid dyes, such as trypan blue and carmine. According to von Möllendorff (1920) vital staining with basic dyes differs essentially from vital staining with acid dyes. He believes that while acid dyes are segregated in cells and so give rise to new formations vacuoles and granules basic dyes differ in that they stain preformed structures. This conception is based upon the fact that it is possible to stain supravitally with certain basic dyes phagocytosed cell inclusions, the yolk granules of some embryonic tissues, and acid dye droplets which have been formed in cells subsequent to the injection of acid dyes. von Möllendorff (1920) carried out a large number of experiments with basic dyes to determine what properties favoured vital staining. He found that the best basis dyes for staining cell granules were those which were only slightly lipoid soluble, but were readily flocculated in contact with acid collids.