Page:Proceedings of the Royal Society of London Vol 1.djvu/31

Rh of the left ear was totally destroyed, and that but a small part of it remained in the right ear. So free was the passage through both the ears, that the patient, by closing his nostrils and contracting his cheeks, could with ease force the air from the mouth through the meatus auditorius; and yet what is most remarkable, the sense of hearing was by no means materially impaired by this imperfection; especially in the left ear, where the whole of the membrane was dissolved. The organ even retained a nice musical discrimination.

From this, and another similar instance here described, it is inferred that the loss of the membrana tympani, though it somewhat diminishes the power of hearing, does not absolutely destroy it; and that probably where this membrane is wanting, its functions are supplied by the membranes of the fenestrae ovalis and rotunda, which being placed over the water of the labyrinth, will, when agitated by the impressions of sound, convey their vibrations to that ﬂuid, in a similar manner as is done by the membrana tympani in its healthy state. It is also intimated that the principal use of this membrane is probably to moderate the impressions of sound, and to proportion them to the powers and modiﬁcations of the organ.

Mr. Home, by whom this paper was communicated, has been pleased to add some additional remarks on the mode of hearing in cases where the membrana tympani has been destroyed; from which we collect that this membrane appears to him to be chieﬂy intended to give an extended surface capable of communicating to the small bones the impressions made upon it, which a membrane Would be incapable of doing unless it had a power of varying its tension to adapt it to different vibrations: and that this membrane being destroyed, there can be little doubt that the impressions of the vibrating air are produced on the stapes, from whence they are communicated to the cavity of the tympanum, and thence to the internal organ. These remarks are added in order to reconcile the present case with the doctrine laid down by Mr. Home in his late paper on the organ of hearing.

Experiments and Observations on the Light which is spontaneously emitted, with some degree of Permanency, from various Bodies. By Nathaniel Hulme. M.D. F.R.S. and 11.3. Read Feb. 13, 1800. [Phil. Trans. 1800, p. 161.]

The light which is the object of the present inquiry must be distinguished not only from that which we derive from the sun, but also from the brightness exhibited by artiﬁcial phosphori, electricity, meteors, and other lucid emanations. The principal bodies which afford the light here treated of, are, 1) Some vegetable and earthy substances, such as rotten wood, and peat earth. 2) Marine animals, some in a living state, viz. the Medusa yhosphorea, the Pholas, the Permatula phosphorea, and the Cancer fulgens; and most of the marine ﬁshes soon after they are deprived of life. 3) Animal ﬂesh in general, some time after the extinction of life. And, 4) Among