Encyclopaedia Britannica, or, a Dictionary of arts, sciences, and miscellaneous literature : enlarged and improved. Illustrated with nearly six hundred engravings > Volume 8, ELE-FOR

316 E R P E T
Phyfio’ogy, '(vith more attention, and in a favourable light, this
1 -i. ]s difcovered to be a beautiful reticulation,
the mefhes of which are vifible to the naked eye.
<f Many obfervations could be made on the texture
of this delicate membrane ; and thefe might greatly
tend to elucidate the nature and origin of the epider¬
mis, which, notwithftanding all the refearches of phy-
fiologifts, are fo little known 5 and newts would afford
frequent opportunities for deeply invelligating the
point.
“ From particular attention to the newts in my pof-
feflion, I have obferved, that there is not the fmalleft
refemblance between this operation and what is exhi¬
bited by caterpillars, and many other infefts. The
Ikin is detached here and there, and often in different
fized plates ; and the change is flow, for it occupies
one or two days, and I have even known it take three.
During fpoliatiorr, the newt continues moving about in
the water, with all the ufual motions of newts that un¬
dergo none j therefore it is no difeafe, and it does not
affedt them as it does infedls. While the change is
going on, the animal darts on its prey, holds and de¬
vours it.,
M Sometimes fpoliation is difficult to be accomplilh-
ed 5 but, in thefe cafes, the newt knows to praftife
certain manoeuvres,, to facilitate the operation, which I
have often beheld with pleafure. It alternately raifes
and depreffes the right arm and left leg at the fame
time, with gentle vibrations of the whole body. It fre¬
quently darts fuddenly towards the furface of the water,
and the next moment precipitates itfelf to the bottom y
and thefe manoeuvres I have feen continued above half
an hour. But the hidden exertion, in all its motions,
indicated that the newt was impatient at the tedioufnefs
of the change.
“ When moft: of the fpoil is thrown off, and the anh
mal, to difengage itfelf from the reft, rapidly rifes to
the furface, it feems carried along in a cloud y for the
whitenefs, finenefs, and femitranfparency of the fpoil,
floating around it, is no imperfed reprefentation of a
cloud.
“ I never obferved-the fingers employed in detach¬
ing the fpoil. Both young newts and thofe full grown
call feveral fucceffive Ikins: fome of large fize are in
my poffeffion, that have done fo before me. Reprodu¬
cing limbs throw off the epidermis as well as the ori¬
ginal.
“ I have feen the Ikin of the head, which formed
like a collar or cravat round the neck, gradually come
down the belly of a large newt that had loft the arms,
and faften like, a tight girdle,
“ Nothing can accurately be faid of the number and
interval of mutations. Between the 14th of July and
the 7th of September, a newt has changed its fldn 11
times.
^ Spallan
xa/ii’s
Trails, ii
368. Dal
ill c
2d
3d
4th
hangt
14th July. 6th change, 9th Auguft.
17th 7th —
2Gth 8 th 19th
24th 9th 24th
30th 10th 26th
ixth 6th Sept,
Zf U's Trav, colour
“ Spoliation fometimes makes a flight change in the
OLOGY- Chap, ir
1 he manner in which toads throw off the old cuticle PhyiioW
is quoted by Dr Shaw, as related by Mr Schneider
from Grignon, who was an eye witnefs of it. “ The
fkin fplits or cracks in a longitudinal dire&ion, both
above and below, and the animal pulls off that of the
left fide with its left foot, and, delivering it into the
right foot, applies it to its mouth and fwallows it. It
then performs the fame procefs on the right fide, and
delivering the cuticle into the left foot, fwallows’it like
the former.”
But the moft remarkable circumftance in the econo,
my of thefe animals is the reprodu&ion of mutilated
limbs, fuch as the legs, the tail, and even the eyes. The
completeft fet of experiments to afcertain thefe curious-
fadls, were made by Spallanzani and Bonnet. The
following is an account of fome of thefe experiments
in the words of the author.
“ Experiment. The right arm and left leg of a nevet
amputated.—On the 6th of June, I cut the right arm.
and left leg off a large newt, very near the body. A
ftream of florid blood fpouted a minute and a half from
each wound ; however, the veffels foon clofed, and the
new t was apparently as w ell as thofe unmutilated. But
it will eafily occur that it did not fwim with equal fa¬
cility.
“ When about a month had elapfed, I began to per¬
ceive a papilla, of a violet gray colour, near the edge
of the trunk or fedtion. This was the origin of a new
arm and leg, which gradually increafed 5 and-.ffom the
14th of July, the two papillae continued growing on the
fubfequent days, but more in length than thicknefs.
They became minute flumps 5 and, on. the firft of Au¬
guft, wereabout two lines long. A kind of cleft, hard¬
ly perceptible, announces the appearance of two toes,
which nature labours to produce,, or rather to expand,
on the new foot. No cleft appears on the originating
a The two toes were eafily recognifed on the 7th*.
They were real miniatures, and truly moft minute. The
flump of the arm continued nearly as it was on the firft
of the month, but is now fomewhat larger j but as yet'
there is no indication of fingers.
“It is pleafing to obferve the little hand fully un¬
folding, while only three fingers of unequal length are
vifible : the middle one is the longeft. The arm has
made no fenfible progrefs. The new foot had four toes-
alfo of unequal length, the firft and fecond of which
are longeft j other two only begin to appear j the fourth
is fcarcely perceptible. One can never tire contem¬
plating thefe miniatures, and admiring the wonders of
the organic kingdom.
Evolution advanced every day. On the 22d of Leg and
Auguft, the regenerated members began to deepen marrarePrC*
colour, fo that the line, diferiminating the old parts <luced‘
from the new, was no longer fo confpicuousj but the
black fpecks on the toes of unmutilated newts were ftill
imperceptible.
I continued my- obfervations on the daily evolution
of the members ; and the following were their dimen-
hons in length, on the 2pth of September.
Old Members,
Arm> 4 lines.
Cubit,, 3*
3
New Members,
Arm,
Cubit,
Thigh,
2f
•Leg,
t