I think we are justified from observation in assuming that the action of ergot may be graded from an almost imperceptible to a very intense degree. Probably the first degree affects the vascular supply; the second, in addition to this, causes so much contraction as to merely render the fibres tense without causing pain; and the third prompts the uterine fibres to vigorous and painful contraction. This inference is plainly deducible, I think, from the several modes by which tumors are made to disappear under its action, as well as from direct observation of the uterine fibres. I will now venture to call attention especially to the manner of expulsion of the polypoid and submucous intramural varieties. It will be seen that when the uterus contracts all the fibres unite in pressing the polypus through the cervical canal, which is usually already shortened, and rendered dilatable in consequence of its increased vascularity. The cervical canal dilates, and after more or less painful efforts the polypus is expelled entire, covered by the mucous membrane. This membrane is often in a {264} state of gangrene, but so far as I have observed these cases the tumor is not broken to pieces. A submucous intramural tumor has a thin layer of fibres separating it from the mucous membrane, and a thick and heavy layer spread over its external hemisphere. A greater part of the muscular wall is therefore applied to the outer side of the tumor. If in this position all the fibres of the uterus vigorously contract, the fibres near the mucous membrane must be overcome by the heavy layer outside. But the opposite wall plays an important part by supporting the weaker layer at the fundus of the tumor, and adding its own force in overcoming the capsule, where it usually gives way. The position of the tumor makes its escape from the concentric action of all the fibres of the uterus impossible, and every one knows that when the resistance is partially overcome the uterus is stimulated to more vigorous action, and the pains will not abate until the mass is expelled. If not too large, it is driven out without undergoing great laceration, but if its size and attachments are such as to make this impracticable, it will be broken into fragments and expelled piecemeal. In subperitoneal tumors there is, next the uterine cavity, a thick and strong stratum of fibres, while immediately under the peritoneum the layer is very thin and comparatively weak. When the uterus is acting with vigor the former contract forcibly, and the mass becomes pedunculated; but that is all, for the tumor lies outside the field of concentric action and escapes the crushing influence to which the submucous variety is subjected. The amount of force exerted upon it is that exercised by the weaker layer of fibres in a state of conquered antagonism, and the rupture of the capsule is impossible.