The experiments of Cushing indicate, further, that operations with removal of the gasserian ganglion produced a dulling or complete loss of the sense of taste in the anterior two-thirds of the tongue, but this loss was followed later by complete recovery. The interpretation of these facts must be that the temporary effect upon the taste sense is only an incidental result of the operation and that the taste fibers for this part of the tongue originate in the geniculate ganglion, which is the ganglion for the facial, or the seventh, cranial nerve, and only get into the lingual branch of the fifth by way of the chorda tympani nerve. Consequently, the chorda tympani, a connecting link between the seventh and the lingual branch of the fifth, is extremely important for the taste sense, since it carries all of the fibers concerned in the taste function of the anterior two-thirds of the tongue. This nerve passes across the cavity of the middle ear, and when stimulated mechanically, chemically, or electrically at this point is said to arouse taste sensations variously described as sour or metallic, sometimes as sweet and bitter. Salt tastes alone have never been reported as resulting from such stimulation. [Illustration: Fig. 3.—Diagram showing some of the various courses which have been advocated for the taste fibers in man. (Courtesy W. B. Saunders Company.)] The taste fibers of the vagus seem to have their cells of origin in the jugular ganglion of that nerve. Thus, while taste fibers are found in the fifth, ninth, and tenth cranial nerves, it seems that the fibers really originate in the seventh, ninth, and tenth nerves. The accompanying figure (Fig. 3.), after Cushing, will show the facts about the distribution of the gustatory fibers. _The Cerebral Taste Centers_ The first unit in the path connecting sense organ of taste and brain, represented by the neurones having their cell bodies in the ganglia described above, all end in the medulla oblongata, in the neighborhood of the fourth ventricle. These terminals, called the primary sensory nuclei for the seventh, ninth, and tenth nerves, are all included in the nucleus of the solitary bundle.