Studies on Occurence and Distribution of Tissue Mast Cells

The morphology, distribution and stainability of tissue mast cells were studied from the tissues taken from selected portions of various organs of the following adult animals; xr«, pig, rabbit. guinea-pig, albino-rat, mouse, fowl, sparrow and frog. And particularly albino rats were selected by different ages 03! gestation day l6-!- g.d., l8t g.d., 19t g.d., 20t g.d., 2It g.d., at birth. 24hrs., Sd, 5d, lad, lfid, 20d, l m, 3m, Gm) and sexes. The following conclusions were made. 1) Tissue mast cells were observed in each species of animals. The density of mast cell population in various organs of various species of animals has shown a sign-ificant difference according to species of animals. It was found that the density of mast cell population is most numerous in cow. pig and dog, being fewer in fowl, guinea-pig, frog and albino rat in the given order, and rarest in rabbit, mouse and sparrow. Numerous tissue mast cells were observed in skin, tongue, lung and gastrointestinal tract of the above animals examined. However, they were absent or relatively few in kidney, pancreas and brain tissues. Histological potrions in which tissue mast cells are abundantly found are a little different according to species of animals. However, they are generally consistant in the organ. The most numerous mast cells were found in the hepatic capsule of cow among the all specimens examined. Tissue mast cells were distributed numerously in connective tissue especially in around blood vessels and gland ducts. However. the density of mast cell population was not always parallel to the amount of connective tissues. The location and arrangement of tissue mast cells in various organs of various species of animals seem to be somewhat peculiar to each species of animals. 2) The form of tissue mast cells of various species of animals was found to be multifarious. It was usually round and ovoid. however the spindle, long. irregular and spined forms were also observed. It seemed to show some difference according to histological portions. Nuclei of tissue mast cells generally correspond to the form of cells and they are uninucleate and situated in central or eccentric portions of cells and commonly stained faintly. Granules of tissue mast cells are usually round, uniform and are mostly compact in their cytoplasm. 3) Tissue mast cells stain red-purplish, purple-bluish or dark purple-bluish, but mostly red-purplish in toluidine blue stain by Rasanen formula. The stainability was mostly distinct. 4) In albino rats. the density of mast cell population in various organs is definitely related with the ag