Dr. R. W. Johnson, who dedicated his _New System of Midwifery_, &c. to Dr. W. Hunter and others, in 1769, and probably attended his lectures, expresses a similar opinion, and says, that in these cases "nature herself will do the work." (p. 267.) Dr. Alexander Hamilton, in 1784, also speaks favourably of these presentations. "The head will, however, in most cases, advance in that position by the force of the natural pains, though the delivery will be more slow or painful." (_Outlines of the Theory and Practice of Midwifery._) Farther experience has shown that, so long as the pelvis is of the natural size, the head can be born in this position without peculiar difficulty, the soft parts usually require a little more dilatation than where the cranium presents, and, therefore, this stage of the labour is generally somewhat slower. Although presentations of the face are not so favourable for the child as those of the cranium, they stand next to them in point of safety. Where the cranium presents, a slight misproportion between the head and pelvis produces little or no increase of difficulty to the passage of the child; but under similar circumstances, where the face presents, the difficulty may become very serious, for if the labour is prolonged, "the brain and vessels of the neck," observes Smellie, "will be so much compressed and obstructed as to destroy the child." (Explanation to table 25.) A similar view has been given by Dr. Denman, and still more recently by Professor Chaussier, of Paris, and Professor Naegelé; the two latter authorities examined the brain in several still-born children where the face had presented, and invariably found the cerebral vessels gorged with blood. The presenting side of the face when born is frightfully distorted by the livid swelling above-mentioned; the mouth is pulled to one side and upwards; the angle of the eye is drawn downwards, and the corresponding ala of the nose scarcely discernible amid the purple mass of tumefaction: the less this is meddled with the better, for in the course of a day or two the parts will have returned to their condition; whereas, if friction or hot poultices, &c., be used, ulceration may be the result, and produce considerable disfigurement.[80]