can have been preserved during exfoliation of that

organ.

But clinical experience decidedly indicates that different parts of the labyrinthine structures are appropriated to the reception of different pitches of sound, since the power of hearing certain notes only may be lost, while the rest are unaffected. Such a case is reported by Magnus, and the power was restored during the use of resonators corresponding to the notes involved. In a patient of my own also, a lady aged 40, with whom conversation could be carried on quite easily, the notes of the upper octaves were entirely inaudible. She had never heard a railway whistle. The pitches of certain notes also may be altered, as if by mistuning of particular strings within the ear. Sometimes there is a difference, as of half a tone, between the two ears. But the true significance of these symptoms is doubtless yet to be found, and it were a pity to preoccupy the ground with conjectures. Variations of fluid pressure of course can hardly account for affections limited to one part of a continuous cavity.

In reference to the effect of section of the semi-circular canals upon the equilibrium of the body, the last experiments appear to show that the effects differ in different animals. Böttcher* found that no movements of turning ensued on careful section of the canals in frogs, and Mr. E. Hart obtained similar results, but Löwenberg* found

* Report in "Journ. Anat. and Phys.," Nov., 1873.

the case different with pigeons. By a modification in the method of operating, he sought to determine whether the movements were caused by pain, as supposed by Flourens, or whether the presence of consciousness was necessary for these disturbed movements, and whether the cause consists in an irritation or paralysis of nerves. The results of his experiments are, (1) the disturbance of movement occurring after section of the semi-circular canals of the ear depends only upon this injury, and not upon any injury to the brain. (2) The vomiting observed by Czermak in his experiments depends upon injury of the cerebellum. (3) The disturbance of movement is the consequence of irritation of the membranous canals and not of paralysis of the same. (4) The irritation of the canals produces the spasmodic movements in a reflex manner without the co-operation of consciousness. (5) The transference of this reflex irritation of the nerves of the membranous canals to the motor nerves takes place in the thalamus opticus. With regard to the statement of Brown-Sequard, that section of the N. acusticus produces these movements, Löwenberg, operating upon rabbits, found that section of this nerve from the tympanum yields the same results, but in this case the semicircular canals are at the same time partly pinched and partly pierced.

It may be hoped that before long Professor Ferrier's experiments will give us a key to the real significance of these facts. The slightest affections of the tympanum,

among others syringing with cold water, or with water much above blood-heat, or the pressure of a column of cold water upon the membrane, will produce giddiness, often extreme; the cerebral centres not only of emotion but of motion being thus eminently liable to be affected thro' impressions on the ear. It seems, therefore, the more remarkable that-in strong contrast to the eyeDr. Hughlings Jackson should have found no lesion of the brain or cerebellum that has deafness for its result, result except thro' mechanically involving the auditory nerve.*

I may add that in one case, that of an elderly lady, long deaf with symptoms of nerve-affection, I have known an attack of hemiplegia distinctly improve the hearing; and quite recently I examined the ears of a woman aged 45, extremely deaf, and found collapse and thickening of the membrane, with great impairment of the nervous power, forbidding all hope of benefit from treatment; her death took place from disease of the heart shortly afterwards, and for more than a week previously her hearing was greatly sharpened.

A curious statement is made by J. A. Nussbaumer † to the effect that both himself and his brother always perceived a sensation of colour, as well as sound, from, every excitement of the auditory nerve whether by music or noises. The colours, however, were not perceived as

* 66

See J. O. Green's Report on

Med. Times and G.," March 1, 1873. +"Wiener Med. Woch.," 1873. 1-3. Otol., "Boston Med. and S. Jl.," Oct., 1873.

external, and they differed for the two brothers with the same note. The statement bears the stamp, perhaps, rather of disease than of any modification of normal function, but may possibly have some significance in the future.

In respect to the functions of the chorda tympani, in one case in which I accidentally divided it in making incision of the membrane, there appeared to be a good deal more than the usual amount of pain, which lasted for three or four days, and taste was much diminished along the whole of the corresponding side of the tongue; it was regained in the course of a fortnight. It has been regarded as acting the part of a regulator of the tension of the membrane by means of a reflex action thro' the tensor tympani; but it seems to me that the observation of cases of disease does not support this view; the hearing better in a noise, which is so frequent a symptom in the less favourable class of cases, seems to have no relation to abnormal conditions of the membrane.

CHAPTER II.

THE DIAGNOSIS OF DISEASES OF THE EAR.

THE diagnosis of diseases of the ear rests on three bases(1) The examination of the various parts of the organ; (2) Tests applied to the function of the nerve; and (3) The history and general condition. First in importance among these is the ocular inspection. The best instruments for the purpose are the simple, round or oval specula, and a reflector such as is used for the larynx; one of more than the usual concavity is very useful; or, by means of a plane one, direct sunlight may be used, and the image of the membrane may be seen on the reflector by others (Lucae). A lens of about six inches' focal distance may be screwed with a joint on the back of the reflector, so that a magnifying power may be used or not, as desired. Ordinary daylight gives the most distinct illumination, and the patient I think is best placed a little farther from the window than the surgeon, not between him and the light.

1

A speculum provided with a prism, to bend the light into the meatus, has been constructed by Dr. Blake, of Boston, and Dr. Eysell has proposed a method which

* "Report of Amer. Otological Society," 1872.