I must call attention to another point that governs the extent and limits of the growth of the tumor--viz. the number and distribution of its vessels. The vessels entering the tumor represent the minute twigs that supplied the fasciculus in which it originated. They arrive at the point of morbid deposit from the parts constituting the capsule, and there are always several of them. The number of these vessels always remains the same, and their calibre is increased with the hypertrophy of the surrounding tissues. They cannot grow at the demand of the trophic energies of the tumor to an unlimited degree, but their size is limited by the growth of the surrounding parts. As the tumor grows and its capsule expands, the vessels are separated farther from each other, until after a while the area becomes so large that the supply of blood will not admit of further growth and the tumor comes to a standstill. Thus their growth, from the nature of their supply, is limited; hence the usual history of the tumor is one of self-limitation. It is all-important in forming an opinion in reference to the greater or less vitality of the fibrous tumor, therefore, to remember that it is not supplied by one large arterial trunk entering at one place and spreading over its capsule, but that the supply is by a number of small vessels penetrating the tumor at different points; that their number cannot be increased and their growth is limited; that as the tumor grows their capacity to supply it grows gradually less until entirely exhausted: then the growth stops. {248} There is another and adventitious source of nutritious supply, and I think it is essential to very large growths: at least, so far as I know, it is always present. I mean the adhesion of the uterus or tumor to the wall of the abdomen, the pelvic or abdominal viscera, or, what is more common, the omentum. When adhesions occur from whatever cause, the vessels of the tumor increase in size and supply it with a vast increase in the amount of blood. All the large tumors I have had an opportunity of examining were to a greater or less extent covered by a network of large vessels contained in the omentum. These vessels penetrate the uterus, carrying a deluge of blood into its substance. These large vascular adhesions are a source of embarrassment in operations for their removal. Operators allude to them and give instructions how to overcome the difficulty presented by them. The uterine vessels alone would never be sufficient to supply the forty- or fifty-pound tumors so often mistaken for ovarian tumors.