It has been observed from the above sketch, that the Ears (the organs Secondly, of hearing,) are of an elaborate complicated structure; which is less un- Hearing derstood even than that of the eyes.(c) No sound can be produced but and its orwith perceptible blast and concussion of the air, and with some resistance gans, the ears. (b) of the air percussed, and the vibrations or tremors excited in the air by such percussion, continue for a short time to move from the place of percussion in concentric spheres to great distances.(d) The ears are so constructed as to embrace, collect, and convey sounds to the sensorium Sounds. commune of the brain, where their principal effect is produced, and sound like light is capable of being reflected from a body at a definite angle, (b) See a valuable article, Coop. Surg. Dict. tit. Ear, 420; 1 Dungl. Phy. 113 to 140; and Curtis on the Ear. (c) See the above plate, and 1 Arnott, El. Ph. 418. The supposition that the tyrant Dionysius constructed a cave, with an aperture, so as to operate perfectly as an ear, seems scarcely credible: "Dionysius made a subterraneous cave in a rock, in the form of a human ear, which measured eighty feet in height, and 250 in length. It was called the Ear of Dionysius. The sounds of this subterraneous cave were all necessarily directed to one common tympanum, which had a communication with an adjoining room, where Dionysius spent the greatest part of his time, to hear whatever was said by those (d) Newton's Optics, 1 Arnott's El. SENSES, CHAP. IX. and concentrated into a focus; and upon that principle it is that echoes SECT. III. are produced, and that the vibrations which constitute sound are increased EXTERNAL by speaking trumpets, domes, and whispering galleries, which, it has been observed, may be regarded as analogous in their operation to convex lenses or mirrors.(e) But as regards musical sounds, and what is termed a musical ear, it is confessed that we are quite ignorant on what the faculty depends.(ƒ) &c. Echoes. The ear has been usually considered under three orders or parts; first, the outward or external part; secondly, the cavity in the temporal bone, called the tympanum, containing also minute ossicles or bones; and thirdly, the tube and nerves conveying the sensation to the sensorium, and these several parts are described in the antecedent plate.(ƒ) The external part of the ear is composed of cartilaginous folds of singular form, and which, from their elastic nature, without having the appearance of a regular apparatus, as in the case of the ear trumpet, nevertheless most effectually receive and collect sounds, and increase their vibrations, (g) and transmit them into the meatus auditorius externus, (h) which is a tube about eleven lines or near an inch long, conveying such sounds into and upon the membrane called membrana tympani, which is stretched across the cavity of the ear, and separates the external parts from the cavity of the temporal bone, where are placed all the parts of the tympanum, or vulgarly the drum of the ear, from its resemblance to one description of that instrument, as well in figure as effect.(i) The latter contains several small ossicles and bones, which vibrate and modify the vibrations of sound, and also serve to communicate with the nervous expansion of or near to the auditory nerve similar in office to the retina of the eye.(j) The auditory nerve conveys the sense of hearing to the sensorium;(k) and it has been conjectured, that the medium by which the undulations of the air are ultimately conveyed to the auditory nerve, is a fluid enclosed in a membrane, which enables it to retain its form, and prevents it from being diffused in the cavity in which it is lodged,(7) as in complete deafness this auditory nerve is, in general, the only organ appearing defective, it may be reasonably supposed that the hearing principally depends on the perfection of that nerve.(m) The Eustachian tube, so named from the anatomist its describer, is a passage extending from the back part of the tympanum into that part of the mouth called the fauces, and which, as will be seen in the plate, is an open passage leading from the tympanum into the fauces, so as to enable the air contained within the drum to have full communication with the external air through the mouth. This is essential to the perfect function of the ear, and if materially obstructed or injured, the sense of hearing will be greatly diminished or destroyed.(n) There are two sets of nerves appropriated (e) 3 Bost. 114, 115. (f) Id. 122 to 125; but see id. 118, n. It is singular to observe, that some are indescribably elated or depressed by varying music, others not in the least affected, and others disgusted, whilst the dog will howl at the most cheerful music, as if he "bayed the moon." (f) 3 Bost. 115, &c.; 3 Horner, Anat. 453 to 474; and 1 Arnott, El. Ph. 418. (g) Instances are recorded of the whole of the external ear having been cut or carried off by a cannon ball, and yet hearing has been still continued; Coop. Surg. Dict. tit. Ear. (h) As to the meatus auditorius and its imperfections, see Coop. Surg. Dict. tit. Ear. (i) As to the tympanum, see Coop. Surg. Dict. tit. Ear; 2 Horner, Anat. 458. (j) As to the ossicles, see 3 Bost. 117; and Coop. Surg. Dict. tit. Ear; 2 Horner, Anat. 461, 462. (k) 3 Bost. 121, n. () Id. 114, n. 119; end of note; 2 Horn. Anat. 468. (m) Coop. Surg. Dict. tit. Ear. See also description of ear in 1 Arnott's El. Ph. 417 to 419; 2 Horner, Anat. 471. (n) 3 Bost. 120; Coop. Surg. Dict. tit. Ear; and see a particularly clear explanation in 1 Arnott's El. Ph. 417 to 419. SENSES, &c. to the ear, one for the immediate purpose of receiving the impression of CHAP. IX. sound, and the other for the general purposes of the nervous influence. SECT. III. The first is termed the portio mollis of the seventh pair of the cerebral EXTERNAL nerves; its fibres are dispersed over the internal parts of the organ, and more especially through the bony canals which communicate with the tympanum, constituting the immediate seat of the sense of hearing. The general nerves are derived from the fifth pair, and are principally dispersed over the muscles of the ear, of which there are many.(0) With respect to audible ideas of distances, they are, it is supposed, Distances. acquired by persons who have become blind after having for some time fully exercised the power of vision, by comparing the strength of impressions of sound with a previous knowledge of the space which exists between the ear and the sounding body;(p) and, with respect to those who were born blind, their audible ideas of magnitude are principally applied in acquiring a knowledge of apartments, which blind persons are often able to estimate with considerable correctness.(p) This they acquire either by attending to the force of the reverberation which is produced from the walls, or by being told the size of the apartments they usually inhabit, and using a certain short pace, that is, one foot, to prevent risk of injury in stepping across it, and also ascertaining the ordinary sound of a voice speaking in the usual pitch, at the entrance or extreme end of the room, and then comparing the effects thus produced upon the ear with that in the case immediately under consideration, and their previous experience, in similar circumstances, will lead to a just conclusion.(p) If a person be born deaf, that is, as it is termed, afflicted with con- Of deafgenital deafness, it follows, that as long as the loss of the faculty conti- ness and nues, he will, also, for the reasons before stated, continue dumb, or, ra- dumbness: ther, his power of speech will continue suspended.(q) If, after having been so born deaf, he should afterwards, as at the age of nine, be cured of the defect, and hear perfectly, he will have great difficulty, and will Occupy much time in obtaining a knowledge of the position of sounding bodies, and still more of imitating articulate sounds; and, in a recorded instance, even after an interval of some months, his powers in this respect were very limited.(r) It appears to have been formerly supposed to be a necessary conclusion, that, if a person be born deaf, he must be dumb, and that, as a further consequence, it is probable he would not write words according to their accent or sound, but merely by imitation of letters and figures;(s) and that if born deaf and dumb, he must, necessarily, be an idiot;(t) and, although the law has since changed, and a person in this melancholy state of privation may evince understanding, and, therefore, may inherit; and, also, on attaining twenty-one, and evincing adequate mind, may manage his property, (u) may contract marriage,(x) and give (0) 3 Bost. 120, 121; Coop. Surg. ing by some instructer in writing without Dict. tit. Ear; 2 Horn. Anat. 471. ever hearing. (p) 3 Bost. 122. (q) Ante, 288, 289. (r) M. Magendie's Journ. vol. v. p. 487; 3 Bost. 122. (8) Ante, 288, note, (t,) citing 1 Par. & Fonb. 371; sed quære whether the experiment of M. Sicard, there narrated, might not be fallacious. If the alleged impostor could write at all, might he not have been taught to imitate the bad spell (t) 1 Bla. Com. 304; and see post. (u) Dickenson v. Blisset, Dicken's Rep. 268, where a lady born deaf and dumb, on attaining twenty-one, claimed possession of her estate, and the Lord Chancellor having put questions to her in writing, to which she wrote sensible answers, gave effect to her claim; and see authorities, 1 Par. & Fonb. 171, 292; and post. (x) Coop. Surg. Dict. tit. ear; and see tit. Deaf and Dumb, vol. iii. Supplement CHAP. IX. evidence by writing or signs, and with the assistance of an interpreter:(y) SECT. II. yet the presumption of idiotcy prevails; and able physiologists suppose, EXTERNAL that dumbness must exist when the deafness was congenital; but the SENSES, &c. Diseases supposition seems erroneous: it is true, that a person born deaf, inasmuch as he cannot hear sounds, or the articulation of words in any language, cannot, unless duly instructed, imitate; and his faculty of speech being suspended, he is incapable of voice to express his ideas, but he is, nevertheless, capable of uttering sounds, and the use of the tongue, as regards speech, seems merely torpid, and if deafness be cured, as at the age of nine years, the individual will, gradually, though with difficulty, be able to imitate words, and, in the course of a few months, be able to speak: (a) and, it is now clearly established, that speech and articulation may be taught, notwithstanding congenital weakness continues; (b) and persons from their nativity deaf and dumb, may (unless otherwise defective in intellectual powers, which is not, by any means, a necessary result,) by proper care and instruction, and the aid of touch and smell, acquire considerable knowledge and intelligence, and even the power of speaking, although to an incumbered and limited extent.(c) With respect to a mere local or particular injury, it is a well-known fact, that those persons who have lost the use of one of the ears, are less able to judge correctly of the position of sounding bodies than those who retain the use of both.(d) The diseases and injuries of the ear are numerous, such as ear-ache, and injuries which, with its treatment, has been ably considered, (e) and the disof ear, &c. eases and injuries, and their remedies, have been also pointed out.(f) Sudden, unexpected, loud vibrating sounds and noises, may occasion death.(g) against negative evidence. Hearing, as As the accuracy of hearing, when the organs are perfect, like that of regards af sight, depends on the degree of attention, and the propinquity to the firmative speaker or the sound, and other circumstances, great discrepancy will evidence, sometimes ensue in the evidence of different persons with regard to weighing what they may suppose they have heard or not heard. Hence, it is a common observation, and, in practice, may be considered a rule, that the affirmative testimony of one witness, whose credit is not, in other respects, impeached, that he did hear a particular expression or sound, is to be given effect to in preference to the negative testimony even of twenty witnesses, who swear that they did not hear the same. Any difficulty of hearing, as it constitutes a natural impediment to the necessary quickness of perception, ought always to constitute an insuperable objection to a juryman; but this is too frequently disregarded in the administration of justice. Thirdly, Sense of . smell. The third sense is Smell, which, however useful and contributing to to Ency. Brit. and Stew. Phil. vol. iii. (y) Rushton's case, Leach, Cr. C. 455; (a) M. Magendie's Journ, vol. v. p. 223; EXTERNAL &c. full enjoyment of life, is, certainly, not essential to man's existence,(h) CHAP. IX. though, in some animals, the sense is so peculiarly powerful, as to enable SECT. III. them to secure their prey, as well known in the instance of sporting SENSES, dogs. The immediate organ of smell is the mucous membrane called Schneiderian, after the anatomist who first accurately described it, and which lines the internal parts of the nostrils, and, especially, the turbinated bones. This membrane is supplied very plentifully with blood vessels and nerves, the latter from two distinct sources, namely, from the first pair, called the olfactory, and from some branches of the fifth pair, and upon the latter of which the irritation is produced, which excites sneezing. The olfactory nerve does not, however, like the optic and auditory nerves, terminate in a filamentous texture, but is reduced to a pulpy substance, which is, as it were, incorporated with the mucous membrane for which it is destined.(h) Desmoulins insists that the branches of the fifth pair of nerves are the only, or at least the principal nerves of smell.(i) The sense of smell will frequently become more delicate by repeated exercise, when the senses of vision and hearing have been suspended, and so as to enable the individual to discover the nature and presence of surrounding bodies.(k) It may be important in judicial inquiries to remember that the effect of habit will, frequently, as regards the sense of smell, reconcile and even attach individuals to the most offensive effluvia; so that in a prosecution or action, it will be found, that the evidence of numerous witnesses of undoubted credit, that they have experienced no unpleasant sensation, will endanger a verdict, whilst the contrary evidence of others, who only, occasionally, have passed near to the nuísance, will clearly establish that to them it was intolerable.() In these cases, if the nuisance be near to a highway, along which all persons have a right to pass, the affirmative evidence of only one or two witnesses of credit ought to be given effect to, and the concurrent testimony of the others wholly laid aside, because habit may have reconciled the nuisance to them; but the individuals of the public who may not live in the neighbourhood have a right to continue and use the public way without such annoyance.(m) As connected with medical jurisprudence, we may observe, that it is laid down that a person might be indicted for murder by laying noisome and poisonous filth at a man's door, to the intent by a poisonous air to destroy him.(n) But it has been observed that we are (h) See Sneezing, ante, 116; respiration, ante, 116; and see a description of the organ, 4 Good, 195, 196; 3 Bost. 131 to 133; 2 Horner, Anat. 403 to 414; 1 Dungl. Phy. 97 to 112. (h) 3 Bost. 131 to 133. (7) Id. 171. (m) Sittings at Westminster, before Lord Tenterden, A. D., MS. The King v. Neil, indictment for a nuisance in boiling bones, &c. near Maiden Lane, leading to Highgate, Mr. Green, in support of the prosecution, swore that the stench was so overpowering, that it was, frequently, with difficulty, and not without spurring, that he could urge his horse to pass the premises, and in certain directions of wind when he approached, the horse would actually turn round ra- (n) Dalton, J. chap. xciii. out of Mr. |