30 
APPL CATION OF THE ARGUMENT. 
tions upon the ear, and the drum of the ear of an elephant. 
[PI. v. fig 4.] He discovered in it what he calls, a radiated 
muscle, that is, straight muscular fibres, passing along the 
membrane from the circumference to the centre; from the 
bony rim which surrounds it towards the handle of the 
malleus to which the central part is attached. This mus¬ 
cle he supposes to be designed to bring the membrane into 
unison with different sounds: but then he also discovered, 
that this muscle itself cannot act, unless the membrane be 
drawn to a stretch, and kept in a due state of tightness, 
by what may be called a foreign force, viz. the action of 
the muscles of the malleus. Our author, supposing his ex¬ 
planation of the use of the parts to be just, is well founded 
in the reflection which he makes upon it: “that this mode 
of adapting the ear to different sounds, is one of the most 
beautiful applications of muscles in the body; the mechan¬ 
ism is so simple , and the variety of effects so great” # 
In another volume of the transactions above referred to, 
and of the same year, two most curious cases are related, 
of persons who retained the sense of hearing, not in a 
perfect, but in a very considerable degree, notwithstanding 
he almost total loss of the membrane we have been de¬ 
scribing. In one of these cases, the use here assigned to 
* As the ear of man and fish has been described, it may not be im¬ 
proper in this place to state, that the other classes of animals are no less 
admirably provided with an ear, adapted to their peculiar habits and 
economy. 
In amphibious animals the organ of hearing has an intermediate struc¬ 
ture; in some species of this class, the ear resembling fish, in others it 
more resembles the formation of terrestrial animals. 
There is an important addition to this organ in birds: viz. a cochlea and 
proper tympanum. 
In quadrupeds we find a more complicated organization; to collect the 
vibrations of sound, they have an external ear, and all those parts, though 
of a different figure, which belong to the human ear. 
The capacity for enjoyment of music is mental, but all the curious 
varieties of sound, which are the source of this enjoyment, are communi¬ 
cated by the mechanical provisions of the ear. We are astonished at the 
varieties of sensation; the ear is capable of perceiving four or five hundred 
variations of tone in sound. 
“ Hence we may conceive a prodigious variety in the same tone, 
arising from irregularities of it occasioned by constitution, figure, situation 
or manner of striking the sonorous body; from the constitution of the 
elastic medium, or its being disturbed by Other motions; and from the 
constitution of the ear itself, upon which the impression is made. A 
flute, a violin, a hautboy, a French horn, may all sound the same tone, 
and be easily distinguishable. Nay, if twenty human voices sound the 
same note, and with equal strength, there will be some difference.** 
Reid’s Enquiry, page 98.— Paxton. 
