I do not know if it will be necessary to mention in this connection that I consider these nuclei identical with the half-moon cells of Gianuzzi, and cannot help expressing my surprise at the physiological importance assigned to them; for they have been considered playing the role of mother cells, giving origin to glandular epithelium formed to take the place of cells used up in the process of secretion. The dark staining, which in section they seem to assume as well as the semilunar form, will be discussed later. Of course I look upon these nuclei as belonging to flat epithelial cells, as we find them lining nerve sheaths, and serous membranes, and consider them of the same physiological importance as the nuclei of such endothelial cells. A similar ensheathing membrane, or membrana propria, I find in the ducts; but here I have not been able to distinguish processes passing in between the cells. If present they must be exceedingly delicate, for it is not difficult to press out groups of cells from the ducts so that empty pieces (short ones of course) of such can be examined. While the membrana propria of the ducts can be separated rather easily from the inclosed cells, it is different from the surrounding network of capillaries. It seems impossible to remove the capillaries from the duct-walls; while, in the gland-structure proper, among the alveoli, the separation of the capillary from an alveolus, can with little difficulty often be accomplished, so that a piece of capillary can be examined without any other structures lying above or beneath it. BLOODVESSELS. It was somewhat surprising to me, and not a little interesting, to find that the ducts have a decidedly richer blood supply than the gland substance proper, the meshes of the capillaries covering the ducts very closely indeed. I will also call attention to the fact that, along the terminal portions of the ducts, no arteries or veins can be seen; and what is still more important, no free nerve-fibres can be discovered. Following the ducts outwards, as these attain larger dimensions, and especially where they give off side branches, we find arteries and veins accompanying them, and there will also be found along-side of them fine nerve-branches. So much is certain, that in that region, where arteries and veins are not to be seen, there are also no separate nerve twigs, and that here the union or coalescence of nerve and tissue which the nerves are to influence must have taken place. If one considers the fine meshes of the capillary network enveloping the ducts, and keeps in mind the abundance of nuclei belonging to the capillary, the membrana propria and the duct cells proper, he can imagine how difficult it must be to follow the course of the nerves through and among all these structures. That it has been impossible for me to separate capillary and membrana propria, has been mentioned. NERVES.