The Distribution of Mast-Cells in the Digestive Tract of Laboratory Animals: Its Bearings on the Problem of the Location of Histamine in Tissues

The mast-cell distribution in the digestive tract of the rat, dog, cat, and guinea-pig was studied. In the rat mast-cells were present in the tongue, oesophagus, and forestomach, but practically absent from the glandular stomach, duodenum, ileum, and rectum. In the other species, mast-cells were numerous throughout the whole of the digestive tract, presenting a large individual variation. In the tongue and oesophagus mast-cells were found mainly in the submucosa and lamina propria, where they were located near the epithelium. In the stomach, mast-cells were more numerous in the mucosa and concentrated in the muscularis mucosae and between the necks of the glands. In the duodenum, mast-cells were also more numerous in the mucosa, being concentrated in the muscularis mucosae and frequently also in the summit of the villi. In the ileum and rectum mast-cells were less numerous than in the stomach and duodenum, keeping the same disposition as in these. The contribution of the mastcells to the histamine content of the digestive tract is discussed.

Note on the Histochemical Localization of Glycogen and Pentosepolynucleotides in the Visual Cells of the Chick (Gallus Gallus)

1. Glycogen was studied in retinas of the chick (Gallus gallus), fixed in Gendre's fluid and stained by the periodic acid/Schiff method. In agreement with some of the earlier data on the subject, obtained with less suitable methods, glycogen was found in the paraboloid of accessory cones and in the characteristically shaped paraboloid of the rods.

2. Basiphilia, observable by means of the gallocyanin-chromalum stain and removable by ribonuclease or perchloric acid, was found in the inner segment of both chief and accessory cones, with the exception of the ellipsoid region.