The Sun.
London, England, 1828-12-25 00:00:00

(Flom Mr. Curtis's Lecture delivered at the Royal Insti-
tution of Great Britain.) •
A hollow cavity seems to be the general stritc-
Aire of the organ of hearing, as best fitted for
receiving and reflecting sound ; in the different
classes of animals it is liable to considerable ra-
rieties in the appearance and manner of its for-
mation, and its -appendages: in man
. the organ
is more perfect in: structure than in '.any 'other
,
animal, and it is also of more importance to him
than to any other animated creature. To enable
us to form proper
ideas on tins important par-
ticular, I shall now make some general observa-
tions on the varied structure of this organ in dif-
All animals, as far as ivcalite:iiiP this
posso-4
ferent animals.
sense ; it %Vas formerly donlieeii ivith respect to
fishes, but the late researches and discoveries 13
eomparative anatomy have sufficiently established
their possession of this sense. In favour of
comparative anatomy oil this subject, Haller, the
father of physiology, justly observes, that the
Situation, figure) and size of partg must be
learned fl•eni lush t their titles awl motions must
be drawn front animals: Curie?, we find, has
divided the aninial kingtlthrt into too !llmit:l'lg,
being a regular gradation train tothplicated. to
simple, through the whole series, beginning
with man, .and terminating with insects found
in a drop of fluid. The fir.a division consists.
of the vertebralia, which extends 'from man to
the eel or serpent. The second is the mo.
lusca, which comprises from . the cuttle fish to,
the barnacle or oyster. The Mird is the articulate,:
extending from-the. crab or' lobster to the earth
worm or leech. The last is the rtqliata,, coca=
prising" from the star fish, or Aledusa; Tcrtm
animalcule of infusfons, The external 'ear and'
tympanum do not extend beyond the vette-
bralia ; nor do they exist in all the animals be-
longing to this division. The impressions which
the organ of hearing
racc;:res are conveyed
through the medium of air ; Him; medium
quires, from the action of the body, comma._,eating sound, a tremulous motion or vibration
.
and as these motions or vibrations succeed ea,
other, mind is impressed or directed to the t?
membrane stretched obliquely across the a.
tory passage, es I have already observed;
it produces a similar motion, and excit,
sense of hearing with a mysterious yet in(
cient precision, a certainty of result in
corresponding to the consecutive causes
In all animals the air is divided into ar
and internal part, and the difference in
time of the organ of hearing is greate,
ternal car than in the external. In q
also, I may observe the difference is n-
than in the other classes of animals ;
ever differences or varieties of structi
with, this we may lay down as a gene,
the animal is better calculated by it
cular circumstances, and mode of li
whole, time sense of hearing may b,
as one of the most powerful means o
animals possess, by its indicating tl
danger; likewise as the means of
individual families, or the c;.
great numbers of a species for the
gration ; also as the guide of most
prey : hence it is an organ that fe
without. The ear is most perfec
blooded animals, and it gradually
proportion to the seeming impo
scale of animation ; thus membrai
to the ear are found in some of the v
animals, and several others which
of sound, though the organ in then
been but imperfectly ascertained.
the external car in quadrupeds it i
monly to resemble the oblique sect
from near the apex to the bases.
other animals exposed to danger,
be attacked by inaa and by beasts.
large cars, and they are partici
backwards, while their eyes at
full and prominent, warn them of
front. Rapacious animals, on
have their cars directed forwards
served in the lion, the tiger, the
External ears are only met witl
four-footed mammalia ; and eve
are exceptions, particularly ar
live in the water or under
are wanting in most of the
duck-billed animals, and
other hand, they have bee,
mote, or mus callus, whir
The same error has been
ing as doubtful the ears o
for they are of an enori
been, according to Blu
in considering their e:
sity. Indeed, the ess
very much agree w'
general form is c,
but the quandru
human subject.
porcupine. I
tilage is stro-
de than tht

',1...

is foitod
444
/0,9 a
a :tail.:
this class,
osdai
higtjelritssin.'
't'lltil they c4l7rtir:licPll.4lll .oidlldee::4 till 4 Irl 1.-1":.
a: et
: r: :se
('ll;'42tia ee;(s
''''j
:
the s
seals
31,
sou I:
17,:cii3Ioe:n :1c :e e
B,ao
lil
1.1 se
chat. t a i 1 2
thei :
lEt 0
3optt
io ,
tee firea
.c ,
48 may, be oh-
;; don:: the
t h ey
fa species
in.rle on uic:sa .1°
ten's eiadzn:leci?je:;(it
icelawi).dctirf-i) dt(josil:a-s.lres ealt:°llllllsaieejs'srtitiladnillekaerit:r::
A as an accidental monstro-
,ential parts of the external ear
Ali those of man, t
insiderabl hough this
y varied ; ill very few
mane are they like those
01; the
though this is the case in the
.n the human ear the external car-
Ager in its structure, and more elate
of any other animal • . •
as the opossum,
byee'c:olrilmithin:alealalillost:nrae(nastalsnseras es order
r(sileti are
id'eoeaftll iiirritift]
irli
itee jeir
Ihr :1
Ce:Le'lli :I: linrri atitanis:: r7e; ;1111Ii:Ori ltbiolf:11.1 'Si:
furnished
1 l) the1
°ise° tSiii) {Thep
1 Ur al:
ieCti telio
••1111:
e the water shrew is a striking example. In
le same manner, in the different genera cf ani-
inals, the external opening, or meatus, varies
considerably with respect to its length, breadth,
and erection. In the duck-billed animals it is
not only very long, but singularly tortuous. In
all the perfect animals or inammalia it may be
almost unnecessary to state they uniformly pos-
sess a lnenibran tympani, a tympanum with it&
eustachian tube opening from that cavity to the
throat ; but in the cetacea there is an exception,
for, instead of the throat, it opens ill the blowing,
vallpre. The membrana tympani is on its outer
surface somewhat concave, being slightly de-
pressed in the middle class, I may here observe, possess the two fenes-
trx, the ovalis filled by the bone of the stapes,
all the animals of this
and the rotunda, at which commences the
scala tympani of the cochlea. ass again In horse and
, different from man, the eustachian tube
does not directly open into the larynx, but into a
sae, situated in the lateral pas of the lower jaw,
and this formation is peculiar to that class only.
111 most of the four-footed inatninalia there is
connected with the tympannin another cavity,
which, from its situation and appearance, may be
compared to the mastoid cells in the temporal
bone of man ;nay, in several animals, this organ/
Would appear to be a mere bony cavity, as iii the
dog, martin, squirrel, hare, and some bisulea. In
cireopitheca there is gnly a Partial developnent
of this structure to be discovered ; hile, on the
other hand, in horned cattle,
and illw the pig, the
cavity we have described is
parted off into cells,
by numerous plates of bone, resembling in some
I,.gree the divisions in a ripe poppy 10 the
head.
warm-blooded quadrupeds there are three ot:sieula

to its size.
the exte.
such a)
the ex'
a Val
they
tur