11 



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 

 e.ars, 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 dis- 

 solved. The organ even retained a nice musical discrimination. 



From this, and another similar instance here described, it is in- 

 ferred 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 in- 

 capable 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, arid 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 A.S. Read Feb. 13, 1800. 

 [Phil. Trans. 1800, jj. 161.] 



The light which is the object of the present inquiry must be distin- 

 guished not only from that which we derive from the sun, but also 

 from the brightness exhibited by artificial phosphori, electricity, me- 

 teors, and other lucid emanations. The principal bodies which afford 

 the light here treated of, are, 1) Some vegetable and earthy sub- 

 stances, such as rotten wood, and peat earth. 2) Marine animals, 

 some in a living state, viz. the Medusa phosphorea, the Pholas, the 

 Pennatula 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 



