S e c t io n V.— Second head o f the Analogical Investigation—;
Inferences with respect to sameness or distinctness o f Species,
derived from the Phenomena o f Propagation between
different breeds.
From .. the c a p a b il^ of propagating or the sterility of
animals sprung Trom -the*" blending of different breeds
it has been supposed that a criterion may be* drawn,
whether the races from which such animals are engendered,
are of the same or of distinct species. It is well
known that mules are in general barren, or incapable of
procreating ; and it has been supposed that all other hybrid
animals—a term applied to the offspring of a male ana female
of different species, are equally sterile. From this "circumstance,
naturalists have attempted to determine what
races of animais are of distinct species, and what breeds ^ are
only accidental varieties of the same species. It has been
concluded, that if the offspring of two individual animals b e longing
to different breeds is_found to be'capaole of procreation,
the parent animals, though differing from each other
in some particulars, yet belong to the same ' species’; if the
offspring so engendered is sterile, an inference has been
drawn that the races from which it descended àrè priginally
distinct.
The great advocate for this doctrine was the celebrated
John Hunter, and sitice the time of Hunter,-it has been
adopted by many óf the most distinguished naturalises.
f)ther writers have” altogether rej ecfced . it as' “an opinion
founded on a hasty and too general induction from a few
facts. I t must be allowed that the exceptions to the supposed
law of nature rendering sterile all hybrid productions,
are very numerous, and that, when they are stated collectively
in the* manner in which this has been done by Rudolphi,*
they have a most imposing appearance, and are well caïeu*
lated to excite our doubt as to the soundness of the general
conclusion to which so many particular facts are opposed,
* Rudolphi, Peytraege zur Anthropologie und allgemeinen Naturgeschichte,
The - casual. intermixture .of breeds, or ;fhe production of
hybrids, is a phenomenon,! observed occasionally in almost
every department jo ï' natui’e^;.and in many instances it must
be admitted that'hybrids have beem found to b e capable of
procreation. \ W e must take a b r i^ sw v e y of -the principal
Observations1 which have been collected in -reference to, this
subjéütL1'
The existence; iof hybrids in the vegetable kingdom is a
fact well known, since the time, of kinpguip, v h ^ ild f e d imagined
this phenomena to be mUch^more fr^,qi^|t an^ f to
take place under a greater variety ®|ul?ir,cuïW;^^h^S
more ^accurate t 'investigation , has b^en^ found >tqij warrant.
Hybrid plants are .continually produced in gajdens|-f|pt^^ja.
proximate iljfeciJjs^by a process,well known ,tó horticulturists.
In th e "state, &f nature-1 .they are yecyjIWfH and although, the
observation of botanists has been , di^cte.4 „Ïpö thiaH spbjpet
during more than oine .^iundred years,, the n um b e r ,.h y b r id
plantS 'as iyht. discovered ,t0 have been produce4: in thft^ wild
and natural condition* of the vegetable tribes* amounts in <tb§
last and1 mdst accurate enumeration only,to forty.* Of/these
it ’ has ? been.| as certained th a t severa! $ b h É f f £?de>
the'ovary be in g> constantly fe'und. a t ; thd • period immaturity
to;-contain no embryo.- This is the case,>of the^ipedic^gg
versicoloTf’iwhich according to M. ,J).e«pandolleris a hybrid
between -M. sativa: andjj falcata; with the ranunculus, > ,da$$-
rus and two otherranunculi, which aijte all hybrids, ''apt
pording to the same writèr, and withjt|%known hybrids of
the i verbascum, digitalis and* polygonum. siTherëj are . two
hybrid centaureee which arehcommonly ;repojted to, b e tferiitip
but M. De Cantdojle says, th a t,h e has ,<^ejyed^;thpm, in
gardens, and has constantly discovered theffi to be f sterile;
With'respect to /a ll the remaining instance%’of hybrids, produced
among plants in thé natural state, it has never been
ascertained whetÖlfthey cap be reproduced or -hoh’';
Among the insect tribes, examples pf irregular unions between
different species are cited >by some. naturalists, but
* Physiologie végétale ou Exposition dès %oe8,«t des fonctions vitales
Végétaux, par M. Aug. Pyr. De Candol^e, tom; ji. 18312,...