VOL. LXXXVII.] PHILOSOPHICAL TRANSACTIONS. 121 



As this experiment had succeeded, I examined the divided tube with attention, 

 to satisfy myself whether its canal was obliterated; and of this I had the clearest 

 proof; for it would not allow quicksilver, nor even air to pervade it. Now here is 

 matter for reasoning. Both ovaries, it seems, bear unequivocal proofs of impreg- 

 nation, but foetuses are found only on one side. Now, on what principles shall we 

 explain these phenomena ? It is certain that neither semen nor the aura seminalis 

 could have touched the left ovary, and yet it bears the most unequivocal marks of 

 recent impregnation. It must depend on some other cause than the actual contact 

 of semen. But an important subject for investigation here presents itself. Why 

 were there no foetuses on the mutilated side; but only the corpora lutea ? Is the 

 application of the semen to the vagina or uterus sufficient to stimulate the oraries 

 to perform their first procreative operations, without enabling them to achieve any 

 thing more ? and does it require the permanent and active energies of this fluid, 

 operating by direct contact on the surface of the ovaries, to produce the full mea- 

 sure of their effects ? But as these are queries which cannot be answered from the 

 mere reflections of the closet, I must engage anew in the business of experimental 

 inquiry. But the first step that ought to be taken in the management of this 

 question, is to give full confirmation to the above fact, by a repetition of the ex- 

 periment; I therefore engaged a keeper of rabbits to procure me 6 in high breeding 

 condition, as soon as possible. 



Exper. Within the space of a month, 1 cut through the fallopian tube on 1 side 

 in 6 rabbits. The season was warm, and consequently favourable for breeding. 

 As soon as they recovered they were admitted to the male: but out of this number 

 2 only were impregnated; and the keeper assured me that one of them had never 

 been impregnated before. When the success in these experiments is compared with 

 that of the former, there was no cause for complaint. Of these 2 which succeeded, 

 1 had 3 corpora lutea and 3 foetuses in the perfect side, with 2 corpora lutea and no 

 foetuses on the imperfect side. The other, which was the virgin rabbit, had 2 

 corpora lutea and 2 foetuses on the perfect side, with 1 corpus luteum and no foetus 

 on the mutilated side. Having now 3 indisputable proofs of this important fact, 

 I consider it a full answer to any objection that Gan be urged on the ground of acci- 

 dental appearance; and that what has been stated above, must, under the circum- 

 stances described, be considered as a law of the part; viz. that the ovaries can be 

 affected by the stimulus of impregnation, without the contact either of palpable 

 semen, or of the aura seminalis. 



But I cannot expect that any physiologist, prepossessed with the common notion 

 of the contact of semen, will yield assent to my position, without subjecting it to 

 a severe scrutiny, and exposing every possible objection to which it is liable. It 

 certainly would not be unphilosophic to ask, why foetuses were not found either in 

 the ovarium, or in the tube between it and the obliterated part, agreeably to the 

 assertion of Nuck, if, as I contend, the ovary was affected by impregnation ? 

 Again, a tenacious opponent might further avail himself of this apparent difficulty, 



vol. xvm. R 



