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26 G L A N D U L A R ORGANS
Contiguous to the outer fide of the dilated end of the vas deferens, -I have
found a bag of confiderable fize filled with a green liquor, which is difcliarged
into the fame funnel with the femen, and probably at the fame time with it (/).
A s there is no proilate gland, it is probable that tliis fac fupplies the place
of it.
Certain anatomifts, I have been told, contend, that the organs we commonly
call veJicuLe Jeminahs are not receptacles of the liquor fecreted by the telles, but
organs capable of fecreting from their inner fur face a prolific liquor, which is
mixed with that from the teftes. To fuch, the defcription I have given of a
veficula containing a green liquor very different from the liquor of the teftes,
which is white, will probably appear a fall confirmation of their new doftrine.
' Y e t I apprehend, that the moft common theory, which fuppofes that the veficula;
are to be confidered as being folcly or chiefly receptacles of the fcmen, is
well founded.
T h i s new dodrine is, I am told, founded on two obfervations.
Firft, on examining the liquor of the veficulse feminales of a man immediately
after deatli, it was found very different in its appearance from the femen
when it is difcharged by a living perfon.
Secondly, that, a confiderable time after caftration, geldings and oxen had
been found capable of generating.
But I would obfer^'•e here, that although the liquor of the veficulas feminales
is indeed very different in colour from the fcmen as it appears when difcharged
in the ufual manner, becaufe it is tlien mixed witli the vifcid and white liquor
of the proftate gland; yet I find it agrees with the liquor in the vafa deferentia
as nearly as the cyftic bile does with the hepatic.
In the next place, we certainly know, that, in fome perfons, difchargcs of the
-femen happen very feldom. That the femen may remain in the veficulas feminales
of a caftrated animal a much longer fpace of time, is extremely probable.
How long fhat fpacc ma^be, bc vcry difficult to determine.
But fuppofing it were poffible to~pf9vc, that, at the time of caftration, there
was not a drop of femen in the veficulse feminales, and yet that afte^^va^ds the
animal was capable of generating, it would not follow from this, that the veficulie
were not the receptacles of the liquor fecreted in the teiHcle. The utmoft
amount of our conclufion would be, that the veficuls feminales, or terminations
of the feminal du£ls, were, capable of fecreting the fame liquor as the beginnings
of thofe duds in the tefticles. Inftances of caftrated animals generating
are, however, fo very rare, as to render it improbable that the veficulze
poffefs fuch a power.
When we throw into the fcale the few following fads, the common opinion
will be found to receive great additional ftrength.
I have already obfervcd the refemblance between the liquor in the end of die
vas deferens and in the veficula fcminalis; we may remark a fimilar correfpondence
in the coats of thefe two parts, and in the cells which thefe form. When
we
(/) S«Tab. XII, E.FF.CG.H.-r.
S E C R E T E D LIQ^UORS IN F ISHES.
wc pour a liquor into the vas deferens, it enters the veficula ftill more readily
than a liquor poured into the hepatic dud does the gall-bladder.
In birds and in the ikate, the dilated end of the vas deferens ferves evidently
the purpofe of a veficula feminalis.
In the dog, the veficula feminales are altogether wanting: yet the ftrudure
of their teftis agrees with that of other animals of the fame clafs, or with that
of birds; and no other difference is obfervable, except that the ftrudure of the
penis is fuch as renders the copulation tedious.
Upon the whole, it appears that the veficulze are receptacles of the liquor fecrcted
by the tefticles, calculated to infpiffate the femen, and thereby render it
fitter for its piirpofe, and at the fame time to prevent copulation from "being
tedious.
T . V .
Of Secretion in the Female Orgmn of Generation, and of the Nutrition of the Foetus.
J N the offeous fifties, the ftrudure of the roe appears to be fimple, and the
ova are fmall.
In the Ikate, we find an ovarium, containing large yolks ; two uterine tubes ; an
organ in each, from which chiefly the glaire of the egg feems to be fecreted ;
two uteri, and, within thefe, eggs with horny ihells («).
T h e beginning of the uterine tubes is tied to the diaphragm, as in the frog :
and hence it is probable that the yolks, before they reach the tubes, float loofe in
the cavity of the abdomen, as happens in the frog {x) ; yet I have never found
an egg of a ftcate in that fituation.
T h e yolk is at laft conveyed by a dud into tlie fmall inteftine of the fcetus,
in the fame manner as in birds and lizards {y).
VI.
Of the fwlmming Bladder of Ftjhes,
T - H e t h e r , in treating of the fecretions of fiflies, an account ought to be
given of the fwimming bladder, and the air it contains, is perhaps a fitter
queftion than at firll fight it may feem to inoft readers.
O n this fubjea, Uliall content myfelf with ftating a few fafts and queries,
leaving the chief circumftances to be determined by more extenfive examination
and experiments than I have leifure for at prefent.
(rO Sec Tab. n. ij. 16. lû. 17. iS. Tab. IX. Q^RR. 5. Tub. XIII. EE. FF.
0) S« Tib. XIV. OP.mJT.b.XIV.
(.)T.b.XVn,0.P,(5.R.S.T.