Studies have been made of a neurovegetative termination within the large salivary gland in cats and men, using SUZUKI's silver method after 10 days' fixation in a 20% neutral formalin. The results of the observation are summarized as follows:
1. Nerve plexuses with numerous ganglion-cells were found either on the surface or the interior of the gland. They are found accompanied by the ducts of the gland and blood-vessels. By the difference of the affinity for silver-salts, the ganglion-cells on these nerve-plexuses can be classified into two groups, i. e. the argyrophil and argyrophobic cells. In comparison with other nerve-plexuses in the alimentary tract, these plexuses seem to have much similarities to those of MEISSNER in the submucous tissue.
2. a) The nerve-plexuses of the parotid gland are found spreading on the surface of the gland, as reported by many other investigators, they seldom extend to the inside of the gland.
b) Of the submandibular gland, however, they penetrated into the connective tissues of the interlobar or interlobular space.
c) Nerve-plexuses are few in the interlobar space of the sublingual gland, and are rarely found in the interlobular space.
d) Lingual glands, especially serous glands, have a small number of nerve plexuses in their interlobar space or in the surrounding connective tissues.
As a rule, the nerve fibers branching out of the nerve-plexuses become mostly unmyelinated and continue branching and anastomosing to form a terminal reticulum in- and outside the basement membrane of the related acinus.
3. In the serous acinus of the salivary gland there generally exist two kinds of nerve fiber. One has a uniform thickness and smooth surface, and winds its way through one acinus to another without being influenced by the basement membrane of the acinus and arrangment of the gland-cells. The other is a hardly stainable fiber, which has many windings and branches making many anastomoses with those from the neighboring acini to form complicated nets inside the acini. Sometimes its ends show a simple form of nerve-ending.
4. In the mucous part generally there exists also a type of nerve fiber as in the serous acinus. The branches of that fiber pass through intercellular spaces into the lumen and end on the free surface of the gland-cells, showing a rosarylike ending, or a delicate net together with fibers of the same kind.
5. Interstitial cells of RAMON y CAJAL are often found among the mucous cells of the salivary gland. Neurofibrils, with which the cytoplasm of these cells is filled, spread out of the cytoplasm to form a thin periterminal reticulum around the mucous cell, particularly around the middle zone.
6. The striated duct of the submandibular gland in a cat has a specific form of nerve-ending, i. e. thin nerve fibers make their way through the cytoplasm and the basal zone between the nucleus and basement membrane. These nerve fibers have many branches and show some dilatation, like small varices or dots, towards their ends. These fibers penetrate into the ducts in the following three ways: they come directly from the terminal reticulum outside the tube, or through the cytoplasm of the myoepithelium, or through the interstitial cells of RAMON y CAJAL.
The parotid gland has in its striated ducts an another kind of nerve fiber which branches at the point of the entrance to the cell through the basement membrane and seems to innervate some adjacent cylinderic epithelial cells.
7. In the interstitial connective tissue of the anterior lingual gland, especially near the main duct in the center of the gland, there occured a capsulated nerve ending which is very similar to the end bulb of KRAUSE in structure.
