SPEC. II. Paracusis obtusa. Hardness of hearing. How formed most advantageously. segment of a circle, by which some degree of power is GEN. II. always lost. The metal of which the tube is made should be that which is found most sonorous, or, in other words, which most completely reflects, instead of absorbing, the sound; and while the funnel or larger aperture is as wide as possible, the extreme end of the pipe cannot be too small. M. Itard has found that a parabolical figure has no advantage over a conical or pyramidal tube: but that the tube is assisted in producing distinctness of sounds by an insertion into it of slips of gold-beater's leaf, at proper distances, in the manner of partitions *. SPECIES III. PARACUSIS PERVERSA. Perverse Wearing. THE EAR ONLY SENSIBLE TO ARTICULATE SOUNDS GEN. II. SPEC. III. THIS is a very extraordinary hebetude of the organ, though it has occasionally been met with in most coun- Physiology. tries. Where it exists, the ear, as in other cases of imperfect hearing, requires to be roused, in order to discriminate the articulate sounds addressed to it, but finds the best excitement to consist in a great and vehement noise of almost any kind †. It consists, according to Cause and Sauvages, who seems to judge rightly concerning it, in a seat of the torpitude or paresis of some parts of the external organ which, in consequence of this additional stimulus, convey the proper sounds addressed to them beyond the mem Traité de Maladies de l'Oreille et de l'Audition. 2 Tomes, Paris, 1821. + Feiliz in Richter Chir. Bibl. Band. ix. p. 555.. disease. GEN. II. SPEC. III. Paracusis perversa. Perverse hearing. Some sounds better stimulants brane of the tympanum, in the same manner as the drowsy or those who are sluggish in waking, do not open their eyes, or admit the light to the retina unless a strong glare first stimulates the exterior tunics. It seems, however, sometimes to depend upon an obstruction of the Eustachian tubes. Under the influence of this species it occasionally happens that particular sounds or noises prove a better stithan others. mulus than others, though equally loud or even louder; as the music of a pipe, of a drum, or of several bells ringIllustrated. ing at the same time. Holder relates the case of a man Mode of treatment. ed to the exigency who never heard but when he was beating a drum*; and Sauvages a similar case of a woman who, on this account, always kept a drum in the house, which was constantly played upon while she was conversing with her husband. The latter gives another case of a person who was always deaf except when travelling in a carriage, during which time, from the rattling of the wheels, he was perfectly capable of hearing and engaging in conversation. And Stahl gives an instance of like benefit derived from the shrill tones of a pipe †. In ordinary cases of practice if we can once hit upon a stimulus that succeeds in giving temporary tone to a debilitated organ, we can often avail ourselves of it to produce a permanent benefit, and sometimes a complete reSumulus of storation, by raising or lowering its power, continuing its sound adaptpower for a longer or shorter term of time, or modifying it in some other way, so as to adapt it to the particular exigency. And it is hence probable that if any of these sonorous stimuli were to be employed medicinally, and with a due respect to length of time, and acuteness of tone, they might, in some instances, be made the medium Illustrated. of obtaining a perfect success. Dr. Birch, indeed, gives an instance of such success in a person who only heard during the ringing of bells; and who, by a permanent use of this stimulus, recovered his hearing altogether . Voltaism may here also be employed in many cases with may prove a perfect cure. Phil. Trans. 1668. No. 26. + Colleg. Casual. N. 76. + Hist. Vol. IV. GEN. II. SPEC. III. Perverse a considerable promise of advantage; and especially in connexion with the ordinary routine of general and local Paracusis tonics and stimulants, as cold, and cold bathing, pungent perversa. masticatories, and injections, bark, valerian, alone or with hearing. ammonia, and a free use of the siliquose and coniferous Voltaism. plants as a part of the common diet. General and local stimulants and tonics. SPECIES IV. PARACUSIS DUPLICATA. Double-Hearing. THE ACTION OF THE ONE EAR INACCORDANT WITH THAT OF THE OTHER; SOUNDS HEARD DOUBLY, AND GEN. II. SPEC. IV. to strabis mus or THIS pravity of hearing depends upon an inaccordance of the auditory nerve on the one side with that on the Physiology. other so that the same sound produces, on each side, a very different effect, and is consequently heard, not homotonously, or in like tones, but heterotonously, or in separate and unlike. And hence this species of morbid hearing, as I have already observed, has a considerable parallelism with that of strabismus or squinting, in which Analagous the optic axis of the one eye is not accordant with that of the other, whence the same object is seen double, and squinting. often in a different position. Sauvages has given two or Singular three very curious examples of this affection. A musician examples. while blowing his flute heard two distinct sounds at every note. The sounds were in different keys, and consequently not in harmony; and as they were heard simultaneously, the one could not be an echo of the other. On another occasion he was consulted by a person who for several months had been troubled with a hearing of two GEN. II. SPEC. IV. Paracusis duplicata. Double hearing. Medical treatment. distinct voices whenever he was spoken to; the one at least an octave higher than the other, but not in unison with it; and hence producing a harsh and insupportable discordancy. This affection is mostly temporary, and, as proceeding altogether from a morbid condition of the auditory nerve, has been cured by blisters and other local stimulants. From not being attended to, however, in due time, it has sometimes assumed a chronic character, when it is removed with great difficulty: and in a few instances it has been connected with a constitutional irritability of the nervous system; in which case a plan of general tonics must cooperate with local applications. SPECIES V. PARACUSIS ILLUSORIA. Imaginary Sounds. INTERNAL SENSE OF SOUNDS WITHOUT EXTERNAL GEN. II. SPEC. V. Analogous to paropsis illusoria ; mostly a nervous affection; and the THIS is in most instances strictly a nervous affection, and bears a striking analogy to paropsis illusoria, or that illusory or false sight in which unreal objects of various forms, colours, and other sensible qualities appear before the eyes. The morbid state is often confined to the auditory nerves, or some of the branches alone; yet it is not unfrequently the result of a peculiar irritability that extends general. through the whole of the nervous system. And occaSometimes sionally it proceeds from an obstruction of one or both the produced by Eustachian tubes. M. Itard ascribes it to two other obstruction causes, both of which are highly questionable: a peculiar state of the blood-vessels, local or general, and an impeded cause may be local or of the Eustachian tubes. The sounds GEN. II. SPEC. V. Paropsis motion of the air in the tympanal cavity*. hereby produced differ greatly in different persons, and sometimes in the very same person at different periods; illusoria. but it is sufficient to contemplate them under the three sounds. Imaginary following varieties, all which the French express by the term bourdonnements: a Syrigmus. Ringing, or tinkling. B Susurrus. Whizzing. 7 Bombus. Beating. A sharp, shrill, successive sound. An acute, continuous, hissing A dull, heavy, intermitting sound. treatment. Heister recommends, in cases arising from a debility of Medical the local nerves, to fumigate the ears with the vapour of a hot vinous infusion of rosemary and lavender; and, where a spasmodic affection of the inner membrane may be supposed to follow upon such debility, he advises a simultaneous use of diaphoretics internally. If it proceed from an obstruction of the Eustachian tubes in consequence of spasm or inflammation, the fumes of tobacco drawn into the mouth, and forcibly pressed against these tubes by closing the lips and nostrils, and then urgently sniffing the vapours upward to the palate, have often proved serviceable by taking off the irritability on which the spasmodic or inflammatory action is dependent. Stimulating the external ear by blisters, or aromatic injections has sometimes availed though not often. Chronic cases are extremely difficult of cure; though I had lately an elderly lady for a patient, who, after having at different cure: times suffered from each of these modifications of illusory sounds for several years, and tried every remedy that could be suggested in vain, at length lost the distressing disappeared sensation by degrees, and without the assistance of any spontamedicine. • Traité des Maladies de l' Oreille, et de l' Audition. 2 Tomes, 8vo. Paris 1821. Chronic cases very difficult of but have neously. |