6lO . PHILOSOPHICAL TRANSACTIONS. [anNO 1755. 



part of the cavity of the tympanum ; is so shaped that it first decreases, as it 

 descends towards the posterior parts of the nose, becoming very narrow; then 

 suddenly diverging, is much enlarged, opening into the posterior part of the 

 nose by an elliptic orifice, a little prominent, turning inwards and forward, placed 

 laterally, and just above the velum pendulum palati. This canal then is com- 

 posed of two distinct cones, the extremities of which unite together, but their 

 bases diverge differently; it is likewise lined with a porous membrane, full of 

 cryptae and mucous cells, continued from and like to the membrane of the 

 nares.* 



When therefore we consider the structure of the eustachian tube, and its free 

 communication with the atmosphere, we may reasonably suppose it subject to 

 inflammation of its membrane, and concretion of its mucus, from cold, &c. 

 like the external meatus ; and though its mucus is of a very different nature, it 

 is nevertheless liable to inspissate by heat, when its thinner parts are exhaled.-^ 

 And from the form cf this passage we may easily conceive, that an obstruction, 

 pretty far advanced, is not to be removed without difficulty, and that in propor- 

 tion, as it is more or less complete, the hearing will be more or less injured. 

 Why then may not this be suspected as sometimes the cause of deafness? per- 

 haps it is not unfrequently so; e. g. When a patient is somewhat deaf from cold, 

 and the outer ear has been examined, and found clear of hardened wax, &c. it 

 is yet not uncommon to find himself suddenly relieved by a great noise in his 

 ear. This is probably owing to the breaking away of the congealed mucus, and 

 the instantaneous rushing of the air into the tympanum ; so that when this dis- 

 order is but slight and recent, nature seems frequently to relieve herself; but 

 when more confirmed, her efibrts are ineffectual for its removal. These consi- 

 derations inclined him strongly to think the hearing might suffer from that cause, 

 and he was much confirmed in it by the following very remarkable case. 



Richard Evans, aged 35, was very deaf in both his ears, yet no visible disorder 

 in the external meatus. It arose from cold, and had subsisted several years, 

 during which time no art or means could procure him the least relief. In 

 August, 1/55, he died of the small-pox, at the hospital in Cold-bath-fields. 

 Mr. W. took that opportunity to examine the eustachian tube of each ear, and 

 found them both stuffed quite full of congealed mucus. This was the only visi- 

 ble cause of his deafness, the other parts appearing in their natural state. As 



* Haller in Boerh. de Auditu, p. 378. Not. e Physiologia. Haller. de Audita, § 485. Valsalva, 

 cap. 2, p. 32. idem fig. xiv.— Orig. 



+ Morganni and others tell us, that they constantly find the cavity of the tympanum in infants 

 always much clogged with mucus ; and Mr. Douglas has often observed the same in adults, and is 

 of opinion that it is concomitant with an obstructed tube in general, and that the injection is equally 

 as effectual as if the tube only was obstructed.— Orig. 



