FOURTEEN FIGURESPeculiar, intraepithelial, mononuclear cells with highly refractile, acidophilic, cytoplasmic inclusions have been observed in different levels of the alimentary tracts of all vertebrate phy1a.l Their discovery is usually attributed to Heidenhain (1888). They have been variously designated as eosiiiophilic myelocytes, as plasma cells with acidophilic granules, as Russell body cells, erythroblasts, erythrophages or other types of macrophzzges, as degenerating cells of one form or another, as atypical mast cells, as mucous cells, as globule leucocytes ( Schollenleukocyten) , as secretory leucocytes and simply as granular cells. Wliile it is probable that these cells are not all alike, even in the same organ and in the same species, there are enough similarities between them, even in different organs and in different phyla, t o suggest that they may be intimately related. Considerable attention has been given the questions of possible origin, interrelationships and functional significance of this general type of cell, but no satisfactory answers are yet available concerning them. Micliels ( '38) comments : "It is still uiicertain whether By far the greatest concentration of these cells which J have seen is in tlw tracheal epithelium of a cat of unknown history. I wish t o thank Mr. R. C.Greulich of the Anatomy Dcpartment a t XcGill Univrrsity for this preparation.
HADLEY HIRKMANa considerable number of more or less specialized techniques were employed for special purposes, eg., new methylene blue, polychrome methylene blue, saf ranin, thionin, toluidine blue and brilliant cresyl blue were used in studying metachromasia ; thionin after digestion with ribonuclease for ribonucleic acid ; the Bauer-Feulgen, Best's carmine and periodic acid-Schiff methods for glycogen; for iron the ammonium hydrosnlphide, dinitroresorcinol, Gomori, hydroxyquinoline, Prussian blue and Turnbull blue methods were used (Bunting, '49) ; for lipoidal substances Nile blue sulphate, the plasma1 reaction, Scharlach R, supersaturated Sudan 111, the Schultz cholesterol test, Sudan black B, Baker's ('46) modification of the Smith-Dietrich method, dinitrophenylhydrazine and Ciaccio 's methods were employed and the globules were examined under polarized light; for the study of the vacuome supravital neutral red was employed; for mitochondria anilin acid fuchsin, iron hematoxylin, Sudan black and supravital Janus green ; for argyrophilia Foot's silver ammonium carbonate, the Masson (Fontana) argentaffin reaction and Bodian's protargol technique were used ; the acetic acid precipitation test, mncicarmine, mucihematin and the periodic acid-Schiff reaction were used for mucins; tests were made for oxidases, peroxidases, acid and alkaline phosphatases, lipases, chlorides and Vitamin C; the reactions of the granules to the biuret, Millon, santhoprotein, Romieu and H y d h (ponceau) tests for protein, to the Baker ('47), Serra ('46) and Thomas ('46) tests for arginine, to the Serra test for sulphydryl, to the diazo, chromaffin and Masson (Fon...