_Liquor amnii._ Where the uterus is distended by an unusual quantity of liquor amnii, its contractile power is necessarily much impaired; and until the quantity of its contents be somewhat diminished, the progress of the labour will be more or less retarded. The average quantity of liquor amnii at the full period of pregnancy is about eight ounces; but it frequently exceeds this very considerably, occasionally amounting to several pints or even quarts. The causes of this extraordinary accumulation are still but little known. "M. Mercier has, in some cases, attributed it to an inflammatory condition of the amnion, the foetal surface of this membrane being stated to have been partially coated with false membrane, and the amnion itself crowded with blood-vessels of a rose colour:" in another case "about a quarter of the foetal surface of the amnion was inflamed, being of a deep red colour and double the natural thickness."[117] The results of Dr. R. Lee's observations, after having paid a good deal of attention to the subject, do not tend to confirm this view: he has described six cases of unusual accumulation of the liquor amnii, in one amounting actually to sixteen pints. In five of them "there existed with dropsy of the amnion some malformed or diseased condition of the foetus or its involucra, which rendered it incapable of supporting life subsequent to birth." In two only of the preceding cases was "the formation of an excessive quantity of liquor amnii accompanied with inflammatory and dropsical symptoms in the mother; and in none did the amnion, where an opportunity occurred for making an examination, exhibit those morbid appearances produced by inflammation, which M. Mercier has described, and which led him to infer that inflammation of the amnion is the essential cause of the disease." (Lee, _op. cit._) Dr. Merriman has given a similar opinion, and states, that "when the embryo or foetus is diseased, the liquor amnii is sometimes immense in quantity. I once saw at least two gallons evacuated from the uterus: the child was monstrously formed and much diseased."[118]