The increasing thinness of the perineum itself, and the frænulum becoming tense during the height of a pain, may be looked upon as warnings that the expulsion of the head is not far distant, and now the support of the hand will be needed to prevent laceration; for this purpose the position on the left side is peculiarly convenient, besides having the additional advantage of relaxing the external parts more completely. If the pains be violent, and the impulse to strain very considerable, we must desire the patient to lie as passive as she can, and do her best not to bear down, for otherwise the head is sometimes driven through the os externum with a single effort, and the mischief done in spite of all our care. The support of the perineum has been variously directed by different authors; we prefer using the left hand, because then we have the right at liberty for any manipulations which may be necessary, such as examining if the cord be round the child's neck, &c. &c. It is awkward at first, because it requires the hand to be considerably twisted, and makes the wrist ache a good deal; but a very little practice soon conquers this slight difficulty, and the superiority of the mode will then be apparent. As our object is not merely to support the perineum, but to direct the head as much forwards under the pubic arch as possible, in order that the anterior portions of the os externum should undergo their share of dilatation, and thus in some measure spare the perineum, the chief pressure should be applied near to the sphincter ani, gradually diminishing it up to the frænulum perinei in front: for this purpose the left hand protected by a napkin (partly for the sake of cleanliness and partly for the purpose of having a firmer hold upon the parts, and preventing it slipping) should now be applied with the palm in the vicinity of the sphincter ani, so that the tips of the fingers should project somewhat beyond the frænulum; the whole should be laid as flat and close to the part as possible. In order that we may be sure of the hand being applied exactly along the raphe of the perineum, we should guide it by the examining finger of the right hand, bearing in mind, that when we place this against the posterior margin of the os externum, and bring the middle finger of the left hand in contact with it, we shall hold the left hand in the desired direction.