. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. '/^:,\^mB III work of a more exact description of each. In figure I is presented the section of a filiform; in figure II that of a fungiform ; and in figure III that of a circumvallate. In all of them the part designated by a represents the epithelium, consisting of squamous and cellular layers; that marked h the underlying mucous membrane. It will be seen at first sight that the epithelium in neither form invests the sub- jacent mucous mem
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. '/^:,\^mB III work of a more exact description of each. In figure I is presented the section of a filiform; in figure II that of a fungiform ; and in figure III that of a circumvallate. In all of them the part designated by a represents the epithelium, consisting of squamous and cellular layers; that marked h the underlying mucous membrane. It will be seen at first sight that the epithelium in neither form invests the sub- jacent mucous membrane as a glove does the finger, so that the outer surface of the former shall present an exact impression of that of the latter. In the filiform papillae it will be observed that the epithelium has a number of long antenna-like excrescences, giving the papillfc the appearance of a brush, while in the others this covering is externally smooth, notwithstanding the inequalities of the underlying membrane h, whose surface exhibits in each example a num- ber of successive and rather narrow eminences of a sugar-loaf or conical form. What purpose the antennte of the first form subserve it is impossible to con- jecture; but, as regards the regular elevation of the proper mucous membrane, their presence alike in each of the three kinds of papillte, as well as the circum- stance of their existence likewise in the outer skin, leads to the conclusion that wherever they occur, whatever otherwise their diversity, the physiological signification which they bear must be the same. Now, as the microscope shows us, that, as regards the outer skin and in part, at least, the mucous membrane of the tongue, the finest branches of the blood vessels and the terminal extremities of the nerves are found in these little eminences, the inference is obvious that this peculiar formation of the surface is imposed on account of the organic eon- tents of the eminences, providing, as it does, suitable receptac
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