570 OBSTETRICS second stage seem to be suppressed like those of a person carrying a heavy burden. The use of the glairy discharge is to moisten and lubri- cate the parts over which the child has to pass, to increase their suppleness and extensibility, and make it more easy for the ovum to slide over the surfaces. "Where these discharges fail to take place, the dilatation of the mouth of the womb is always more painful and slower, and the organs are more disposed to become inflamed. The name of bag of waters is given to a protuberance formed by the membranes in the upper part of the vagina during labor. During the presence of a pain, it is hard, tense, and elastic ; after the contraction is over, it becomes wrinkled and contracts or disappears. It eventually breaks, sometimes early in the first stage, and in other cases not until late in the second stage, when the contained fluid escapes. The duration of labor is exceedingly variable, even when no obstacle opposes its natural course. Some women are delivered in an hour or two, others only after several days ; and between these two extremes there is every intermediate grade. In the first confinement, the average length of labor is usually from 10 to 12 hours ; but in at least one case out of five it may not terminate under 15, 18, or even 24, and this without any injury whatever re- sulting either to the mother or child. Women who have had children are delivered much sooner, only suffering, in ordinary cases, about 6 or 8 hours. The duration of the first stage is to the second as 2 or even 3 to 1 ; but this law is subject to many exceptions. The third stage ought to be completed within 30 min- utes. To understand the mechanical phenom- ena of labor, it is necessary first to define the terms presentation and position. We desig- nate by the term presentation the part of the child that first offers at the entrance of the pelvic cavity ; and by the term position, the relations of the presenting part to the differ- ent points of the entrance to the pelvis. The attitude of the child in the uterine cavity is in a great majority of cases such that the direc- tion of the trunk is parallel with that of the mother, and one extremity forms the most de- pendent part. If the head is flexed, it is called a vertex presentation. If the head is extended back, the chin far removed from the breast, it is a face presentation. When the other ex- tremity presents, the legs are usually flexed on the thighs and the latter on the abdomen ; the whole breech may therefore offer at the en- trance of the pelvis, or one or both feet or knees. As the mechanism of labor must be the same in all these cases, they are all in- cluded under the term pelvic presentations. But it may happen that, instead of one of the extremities offering, some portion of the trunk may offer, the child lying transversely in the uterus, and this may be either some point of the right half or of the left half of the trunk. We have then five primary presentations, one of the head, one of the face, one for the pelvic extremity, one for the right lateral plane, and one for the left lateral plane. The presenta- tion of the head is incomparably more frequent than all the others. According to Mme. Boi- vin, in 20,357 cases it occurred in 19,730. The foetus presents by the face, on an average, once in 250 labors. The pelvic presentation occurs once in 30 or 35 labors. The trunk presen- tations are a little less rare than the face, oc- curring about once in 200 cases. As a law it may be said that trunk presentations always demand the interposition of art to accomplish delivery. The other presentations generally terminate spontaneously. In order that a la- bor may terminate without foreign aid, there must be on the part of the mother no fault or deformity of the pelvis, no serious affection of the womb, and the organ must possess a certain energy ; the general powers of the system must not have been exhausted either by a profuse haemorrhage or any long continued disease ; there must be no affection making it danger- ous for the woman to give herself up fully to the efforts that she is compelled to make ; and no accident must supervene during the labor. On the part of the child, it is important that it should descend with the head, the face, the feet, the knees, or the breech foremost, and that it should not be of a size disproportionate to the capacity of the pelvis. About one case in 30 requires in some form artificial aid to complete a happy delivery. The obstetric op- erations required for cases of difficult and dan- gerous labor, either to save the life of the moth- er or child or both, are : 1, induction of prema- ture labor, an operation of great importance and value in certain cases ; 2, version or turn- ing, that manual operation by which one pre- sentation is substituted for another less favor- able ; 3, the vectis, to correct malpositions or aid the natural rotations of the head ; 4, deliv- ery by forceps ; 5, craniotomy, an operation by which the life of the child is sacrificed in order to save the mother; 6, the Caesarean section, in which the child is extracted through an in- cision in the walls of the abdomen and uterus. The dangerous complications which may arise in connection with labor are i prolapse of the cord or funis, an accident very fatal to the child ; flooding or haemorrhage ; retention of the placenta ; convulsions ; rupture of the ute- rus ; lacerations of the vagina or perineum ; and inversion of the uterus. The progress of obstetrical science and the improvement in the art have been very marked in recent times. According to Tanner, " the 20th annual report of the registrar general of births, deaths, and marriages in England shows that in the year 1847 the birth of every 10,000 living chil- dren was the death of 60 mothers, whereas in 1857 it was only fatal to 42 ; hence 18 mother? are now saved in every 10,000 children born. Since 1848 the decline has been progressive, the numbers per 10,000 being 61, 58, 55, 52, 47, 47, 44, and 42 in 1857." Among the most striking modern improvements in obstetrical
