409 



The liquor atrinii is a serous fluid, of a sweetish odour, of insipid taste, 

 rendered slightly turbid by a milky substance which it holds suspended, 

 and somewhat heavier than distilled water, 1,004. It is almost complete- 

 ly aqueous; albumine, soda, muriate of soda, and phosphate of lime, dis- 

 covered in it by MM. Buniva and Vauquelin, forming only 0,012 of the 

 whole mass. It turns of a green colour, tincture of violets, and reddens 

 that of turnsol; a very remarkable circumstance, as is observed by the 

 last mentioned philosophers and indicating the co-existence of an alkali 

 and of an acid in a separate state. The latter is, in so small a quantity, 

 so volatile, and so soluble in the liquor amnii of woman, that it has never 

 yet been obtained by itself: there is found, however, in the liquor amnii 

 of the cow, a peculiar acid, called by MM. Buniva and Vauquelin the 

 amniotic acid. The liquor amnii is in greater quantity, in proportion to 

 the size of the foetus, according as the latter is nearer the period of its 

 formation. It is the product of arterial exhalation. Its materials are 

 supplied by the bljod conveyed by the vessels of the uterus. This is 

 proved, not merely by analogy, but likewise by observing the connection 

 between the qualities of the liquor amnii and the regimen of the mother. 

 In a woman who had used mercurial friction, in the course of her preg- 

 nancy, the liquor amnii was observed to whiten copper*. 



The fundus of the bladder, in quadrupeds, is continuous with a canal, 

 of which the rudiments are observed in man, and which is called the ura- 

 chus. This canal joins the umbilical vessels, passes out with them at 

 the umbilicus, and terminates in a membranous sac, between the chori- 

 on and amnion ; it is called the allantois: it is always found in the foetus 

 of the. lower animals, but it is very indistinct, and often does not exist in 

 man. Some anatomists say they have seen the urachus sri sing from the 

 human bladder, and which is commonly ligamentous, terminate in a 

 small vesicle, which some of them compare to a melon seed ; while 

 others say its bulk does not exceed a millet or hemp seed. So small 

 a vesicle can certainly answer no purpose; the urachus always forming 

 a solid cord, seldom pervious, and even of very small bore, in- the part 

 nearest the fundus of the bladder. The existence of these parts furnishes 

 an additional proof.of what was stated in speaking of the uses of the valve 

 of the caecum, viz. that there are in the animal body, organs which an- 

 swer no purpose, and' which merely indicates the plan which Nature has 

 followed in the reproduction of beings, and the gradations which she has 

 uniformly observed in the divisions of the speciesf. 



CCXV. Of the natural term of gestation. The foetus may exist 

 without the maternal influence, when arrived at the period of seven or 

 eight months from the instant of conception. All accoucheurs agree that 

 it may be delivered alive, at this period, and that it stays two months 

 longer in the uterus, only that it may gain more strength, and be better 

 fitted to resist the new impressions which it is to experience, on coming 



from the irritation excited by the act of impregnation. It serves to unite the ovum to 

 the interior of the uterus; and, although the ovum may never reach this viscus, the de- 

 cidua is developed, notwithstanding, on its internal surface. This circumstance is al- 

 ways observed in extra-uterine fetation. 



* M. Laissaigne has discovered a gas composed of 78,3 of azote, and 21,7 of oxygen 

 in the liquor amnii of some inferior animals. This gas is respirable and supports 

 combustion .See Archives de Medecines, Juin. 1823. 



t See the APPENDIX, rfote 1 1. 



3 F 



