Although these statements are undoubtedly true, it may nevertheless be asserted with confidence that we are to-day no longer in the dark as to the general pathology of this interesting disorder, and that we are in position to map out a plan of treatment which meets the indications which present themselves in an intelligent and reliable manner. There are, however, several sources of hemorrhage which result in pelvic hæmatocele, and it is highly probable that the day will never come when that one which has created the accident can be ascertained with certainty. But while such accuracy of diagnosis would be gratifying to the ambition of the modern diagnostician, neither the prognosis nor treatment of the disorder would be influenced by it. Long before our day practitioners had recognized by touch the occasional presence of tumors, more or less marked by fluctuation, which occupied the pouch of Douglas, and by their mechanical influence pushed the uterus out of its normal place; but it was not until the early part of our century that it was discovered that these tumors were sometimes, and that not rarely, composed entirely of coagulated blood; and, curious though it may appear, it was not until the year 1850 that pelvic hæmatocele became a well-recognized disorder. As early as 1737, Ruysch of Amsterdam appears to have come to the verge of discovering it, but it was left for Récamier, to whom gynecology owes so much besides, to make it known when in 1831 he opened a post-uterine tumor, gave vent to a large accumulation of coagulated blood, and described the case in the _Lancette Française_ for that year. In 1850 the {240} subject attracted the attention of Nélaton, became a recognized pathological condition, and has since received a great deal of attention in all the civilized countries of the world. DEFINITION AND SYNONYMS.--Pelvic hæmatocele--which has likewise received the names of retro-uterine hæmatocele and uterine hæmatoma--may be defined as an effusion of blood into the pelvic cavity of the female, either into or under the peritoneum. Some authors have limited this definition to blood escaping from utero-ovarian vessels and to blood enclosed either by anatomical structures or by previously-existing inflammatory products. I do not adopt these restrictions, because their assumption appears to me to be unwarranted and the validity of the reasons given for their adoption more than doubtful. The location of the blood-mass differs widely in different cases: sometimes, and usually, it is behind the uterus--high up when obliteration of Douglas's pouch has occurred, low down and near to the perineum where such obliteration has not occurred; at other times it exists both behind and in front of the uterus; and at others still, in front of the uterus alone, adhesions preventing its percolation to the posterior parts of the pelvis.