Although it is so important that we should lose no time, still nevertheless it does not appear desirable to operate before labour has commenced to any extent; for unless the os uteri has undergone a certain degree of dilatation, it will not afford a sufficiently free exit for liquor amnii, blood, lochia, which, by stagnating in the uterus after the operation, would soon become irritating and putrid, in which case they would be apt to drain through the wound into the abdominal cavity and create much mischief.[99] _Different modes of operating._ The incision has been recommended to be made in different ways by different authors; but the highest authorities, as also later experience, combine in favour of that in the linea alba. Richter states, that one great advantage from making it in this direction is, that when the uterus contracts and sinks down into the pelvis, the incision in it still corresponds with that through the abdominal parietes, and therefore admits of a free discharge of pus, &c. through the external wound; whereas, if it have been made to one side, viz. at the outer edge of the rectus abdominis muscle, as recommended by Levret for the purpose of avoiding the placenta, the wound in the uterus when contracted ceases to correspond with it, and the discharge escapes into the abdominal cavity. Besides this the abdomen is usually more distended at the linea alba; the uterus here lies immediately beneath the integuments; the intestines are usually pressed towards each side; and therefore when the incision is made on one side they frequently protrude, a circumstance which rarely happens when it is made in the linea alba, except perhaps towards the end of the operation. In the linea alba we have only to cut through the external integuments in order to reach the uterus, while at the side, we have to cut through considerable layers of muscle.