OF REPRODUCTION. 101 



embryo half in the tube and half in the ovary, as reported by Bus- 

 siere, requires some new evidence; though a great many cases of 

 extra-uterine pregnancy, examined with care, are very far from being 

 conclusive, the experiments of Nuck, who placed a ligature on the 

 tube, betwixt the womb and ovary, direcUy after copulation, and 

 upon killing the animal some time afterwards, found that fecundation 

 had taken place, and that the ovum, stopped by the thread, had be- 

 gun to develop itself in the ovarian moiety of the seminiferous canal; 

 those of Haighton, who found that fecundation did not take place in 

 rabbits on that side where he had tied the tube, &c., appear to prove 

 incontestably, that the union of the germs does not take place in the 

 womb. 



, 257. Mechanism. As to the mechanism of this union, it is still 

 covered with an extremely thick veil. After coition, one of the 

 vesicles enclosed in the ovary enlarges with great rapidity, soon 

 rises above the surface of the organ, gradually thins its coat, which 

 at length bursts; when this vesicle bursts, a much smaller vesicle, 

 which is the real germ, escapes from it (239); this germ engages at 

 once in the tube, which mean while was spasmodically applied, like 

 a cupping-glass, to the portion of the ovary from which, during a 

 fruitful coition, the vesicle escapes. 



258. The capsule which contained the germ before it was rup- 

 tured, constitutes what has by Valisnieri, Santorini, Cruikshank, 

 Buffon and Home, been called the yellow body {corpus luteum); its 

 rupture occasions a small bleeding wound, which cicatrises by de- 

 grees, and leaves in its place a wrinkled or depressed scar, more or 

 less deep, and which Littre, Haller, and some others mistook for the 

 real yellow body. 



259. That which takes place in regard to a single ovule, may 

 also occur to two, to three, or a greater number. Supposing that 

 the evolution of the ovule is put in play by the commotion that ac- 

 companies coition, by a sort of electric commotion, by an aura 

 seminalis, by means of an animalcule, or by any principle whatsoever 

 of the prolific matter; that this principle reaches the germ directly 

 from the woman, or that it reaches it only after having passed through 

 the general circulation, it always happens that after a fecundation 

 has been effected, there is detached from the ovary an ovule so mo- 

 dified, that it is soon recognised as a being similar to the one that 

 produced it. This is what is demonstrated by observation; but we 

 know nothing further about it. The systems of preformation or evo^ 

 lution, of emboitement or panspermy, of epigenesis and catageitesis, 

 expansive force, resisting force oi ihe ancients; the nisus formativus 

 of Blumenbach, reproduced tmder a new point of view, and clothed 



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