400 



the term of gestation, let us consider, a little, this fruit of conception ; 

 let us study its developement, let us examine the nature of the relations 

 which it holds with its mother. 



CCVIII. History of the fcetus and its coverings. The interior of the 

 uterus, for a short period after the instant of conception, shows nothing 

 that leads to a knowledge of the existence of its product. But, at the end 

 of a few days, there appears a membranous transparent vesicle, filled with 

 a liquid trembling jelly 5 discovering no trace of organization and life. 

 But the little ovum begins to grow, parts of the gelatinous fluid assume 

 more consistence, losing, at the same time, their transparency : one may 

 then distinguish the first rudiments of parts, an imperfect appearance of 

 the head, trunk, and limbs. The small ovum, free at first in the cavity 

 of the uterus, contracts adhesion to this viscus: its whole exterior sur- 

 face becomes shaggy, and this sort of vegetation is no where more mark- 

 ed, than in the situation to be occupied by the placenta. Meantime, to- 

 wards the seventeenth day, the p ! arts which showed merely a homoge- 

 neous semi-transparent mass, discover a more determinate structure. A 

 red point appears in the spot of the heart, it is the heart itself, distin- 

 guishable by the pulsations of its cavities, and the motions of the mole- 

 cules of the red liquid that fills them. Because the heart is the punctum 

 baliens, it is not therefore to be concluded that it is \X\tprimum vivens. All 

 our parts are formed together, all are coeval, as Charles Bonnet has said; 

 only they discover themselves earlier or later to the eye of the observer, 

 according as the nature of their organization is adapted to the reflection 

 of light*. Were we to admit a successive order in the formation of our 

 organs, the brain and the nervous system might exist before the heart, 

 without being perceptible from their transparency. 



Meanwhile, red lines, setting oft' from the heart, sketch the course of 

 larger vessels, and seem agitatated by the action of these tubes, whose 

 parieties are still semi-transparent. As the blood, or rather its red part, 

 extends from the centre to the circumference, the forms become more 

 determinate, the parts unfold and grow rapidly : points quite opaque, are 

 seen, and the form of the foetus may be distinguished. Bent upon itself, 

 the foetus is not unlike a French bean, suspended by the umbilical cord, 

 which, as I shall mention by and by, formed with the foetus and its co- 

 verings, proceeds in growth with them: it swims amidst the liquor amnii, 

 cnanges its position the more easily, as the space, in which itis enclosed, 

 is greater, compared to its size. As it grows, it stretches out a little, 

 without ceasing, however, to retain hs bent posture CLXV 1 :) the head 

 composes the greater part of its body : the upper limbs, like little buds, 

 pullulate first, then the lower limbs: the feet and the hands appear im- 

 mediately attached to the trunk : the fingers and toes show themselves 

 like little papillae. Of all the organs of sense, the eyes are the first ap- 

 parent: they are discernible, as two little black spots, by the end of the 

 first month ; the eyelids are produced and cover them. The mouth, at first 

 gaping, closes by the drawing together of the lips, towards the end of 

 the third month. During the fourth, a reddish coloured fat begins to be 

 disposed in the cells of the mucous tissue, ancbthe muscles already exert 

 some action. The growth is ever more rapid, as the foetus draws nearer 

 to its birth. It is impossible to assign the weight and the length of the 



* The opinion of Bonnet alluded to above, rests on no observation that can even lend 

 it a collateral support. We have every reason, on the contrary, to infer, that a succes- 

 sive order in the formation of our organs is observed. See some remarks on this subject 

 ui the ArrusDii'. Note 1 1. 



