Abstract
Certain of the free-living and associated protozoa have been selected for a preliminary study of their reaction to the Feulgen thymonucleic acid test. They have been considered as to their status, source, nuclear organization and their reaction to this test. Extra-nuclear inclusions and organelles have received attention, as well.
Thymonucleic acid has been found to be present in some portion of the nuclear apparatus of each protozoan tested, thus far. Whether it can be said that the Feulgen reaction is indicative of the presence of chromatin is somewhat doubtful.
In Paramecium multimicronucleatum and Paramecium aurelia, both the macronucleus and micronuclei of each species gave a decidedly brilliant purple color reaction, while in the “associated” protozoan, Balantidium coli from the guinea pig, the macronucleus was a brilliant purple and the micronucleus a pale violet or negative. Presumably the micronuclei play similar rôles in the life-history of the two ciliates. Division stages of these two forms have not yet been secured for use in this reaction.
The food vacuoles of Paramecium contain bacteria and other ingested food particles. These vacuoles gave a faint violet reaction, which was due doubtless to the presence of the bacteria. The remainder of the protozoan was colorless.
The presence of host intestinal epithelial cells within the endoplasm of Balantidium was definitely established. The nuclei of these host epithelial cells gave the same reaction within the protozoan body as did those nuclei in situ, in the same field of the microscope.
The macronucleus of Balantidium coli showed vesicular areas similar to those previously described by the author 1 for the same species. In the Feulgen preparations these areas appeared as clear colorless vesicles, as they did when stained with alum cochineal, in contrast to their intense dark staining in Heidenbain's Iron Haematoxylin.
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