FOE 



FOL 



Of the Uterus and its Contents in the earlier 

 Months of Pregnancy. 



The conception at first is lodged en- 

 tirely in the 1 undus uteri ; and no part of 

 it extends into the cervix ; which, on the 

 contrary, remains contracted and hard, 

 and nlled with a tough and firm jelly. 

 The neck, however, is gradually distend- 

 ed, so that at last there is no distinction 

 between it and the fundus. 



The corpus luteum is larger and more 

 vascular, and contains a cavity filled with 

 fluid. 



There is a small membraneous bag 

 placed on the outer surface of the amnion, 

 and connected to the navel-string, called 

 the vesicula umbilicalis. 



The chorion is at first covered all over 

 with fine shaggy and floating processes, 

 which are continuations of the umbilical 

 vessels. By these it adheres to the de- 

 cidua, and derives its nourishment and 

 supply. These processes are the foetal 

 portion of the placenta at that time. As 

 the ovum increases they disappear from 

 the general surface of the chorion, be- 

 come confined to one part, and form the 

 fleshy part of the placenta. 



The decidua is most manifest in the 

 early state of conception, and is thickest 

 at that time. It adheres to the uterus by 

 numerous fine flocculent processes. It 

 is formed by the uterus previously to the 

 entrance of the ovum into its cavity; and 

 is even formed in cases of extra uterine 

 foetus, where the ovum never enters the 

 uterus. 



The placenta does not exist in a very 

 young ovum. The whole outer surface 

 of the chorion is covered with shaggy 

 vessels. In the course of a few weeks 

 one half of the membrane becomes 

 smooth, the remainder being covered as 

 before. These vessels, at their floating 

 extremities, are covered with decidua ; 

 and these parts, which at first are separa- 

 ble, gradually become intimately connect- 

 ed, and form a firjn mass adhering to the 

 uterus, which is the placenta. 



The navel-string is not visible till to- 

 wards the sixth or seventh week. 



The foetus is discernable about the 

 fourth week after conception. In a par- 

 ticular instance, a very small foetus was 

 discernable, where, from peculiar cir- 

 cumstances, the conception was clearly 

 ascertained to be twenty -two days old. 



Towards the end of the second month 

 it consists of two oval masses, the head 

 and trunk; of which the former is bent 

 forwards upon the chest ; the eyes are 



very conspicuous, and form large black, 

 prominences ; the mouth and tongue are 

 discernible ; the body forms a larger and 

 longer oval than the head, with the low- 

 er part of the spine curved towards the 

 belly: the upper extremities sprout out 

 from each side of the chest; and the 

 lower from the lower part of the trunk, 

 being considerably smaller than the up- 

 per. 



FOG, or MIST, a meteor consisting of 

 gross vapours, floating near the surface of 

 the earth. See METEOROLOGY. 



FOIL, among glass-grinders, a sheet of 

 tin, with quicksilver or the like, laid on 

 the backside of a looking-glass, to make 

 it reflect. 



FOIL, among jewellers, a thin leaf of 

 metal placed under a precious stone, in 

 order to make it look transparent, and 

 give it an agreeable different colour, 

 either deep or pale. Thus, if you want 

 a stone to be of a pale colour, put a foil 

 of that colour under it ; or if you would 

 have it deep, lay a dark one under it. 



FOLIATE, in the higher geometry, a 

 name given by M. de Moivre to a curve 

 of the second order, expressed by the 

 equation x?>-\-y^a x y ; being a species 

 of defective hyperbolas with one asymp- 

 tote, and consisting of two infinite legs 

 crossing one another, and forming a sort 

 of leaf. 



FOLIATING of looking-glasses, the 

 spreading the plates over, after they are 

 polished with quicksilver, &c. in order to 

 reflect the image. It is performed thus : 

 a thin blotting paper is spread on the 

 table, and sprinkled with fine chalk : and 

 then a fine lamina or leaf of tin, called 

 foil, is laid over the paper ; upon this 

 mercury is poured, which is to be dis- 

 tributed equally over the leaf with a 

 hare's foot, or cotton : over this is laid a 

 clean paper, and over that the glass-plate, 

 which is pressed down with the right 

 hand, and the paper drawn gently out 

 with the left : this being done, the plate 

 is covered with a thicker paper, and load- 

 en with a greater weight, that the super- 

 fluous mercury may be driven out, and 

 the tin adhere more closely to the glass. 

 When it is dried, the weight is removed, 

 and the looking-glass is complete. Foliat- 

 ing of globe looking-glasses is done as 

 follows: take five ounces of quicksilver, 

 and one ounce of bismuth ; of lead and 

 tin half an ounce each. First put the 

 lead and tin into fusion, then put in the 

 bismuth, and whrn you perceive that in 

 fusion too, let it stand till it is almost 

 cold, and pour the quicksilver into it t 



