Philosophical Society of London. 459 



from the Hebrew, Arabic, Greek, Latin, French, Italian, 

 Spanish, German, and English languages, but even from 

 the Indian, African, and Mexican, as Mr. J. M. Good has 

 shown, in a paper on Medical 1'echnology, in the first part 

 of a new series of the Transactions of the Medical Society 

 of London. Notwithstanding the many difficulties which 

 thus presented themselves in the demonstration, Mr. P., 

 conscious of the utility of publicly disseminating so im- 

 portant a branch of knowledge, was emboldened to proceed 

 to his subject *' with ait its imperfections on its head." 



The ear he divided, in common with anatomists, into eK- 

 ternal and internal ; the former, comprehending the lobulus 

 pinna and meatus auditorius externus; the latter, ^the 

 tympanum, labyrinth, and meatus internus. These several 

 parts, together with the Eustachian tube and the auditory 

 nerves, were perspicuously demonstrated by diagrams and 

 preparations, and rendered intelligible to the audience. 

 After this, Mr. P. proceeded to consider sound and its 

 effects, and to apply them to the phaenomena of hearing, 

 lie traced the sonorous undulations passing through the 

 air collected into the concha, and conveyed along the ca- 

 nalis auditorius to the membrana tympani, where he no- 

 ticed the discovery of a radiated muscle by Sir Everard 

 Home, first in the elephant and afterwards in man, by 

 which the membrane is brought into a state capable of 

 acting, and of giving those different degrees of tension 

 which empower it to correspond with the variety of ejc- 

 ternal^ tremors : when the membrane is relaxed, the ra- 

 diated muscle cannot act with any effect, and external tre- 

 mors make less accurate impressions*. From the mem- 

 brane he traced the progress of sound along the ossicula 

 auditus, and considered the muscles belonging to them. 

 From the last of the bones (the siapcs) he traced it through 

 the fenestra ovalis into the vestibulum and semicircular 

 canals, and treated of the meuibranes lining those cavities, 

 the fluid contained in them, and the nerves expanded upon 

 the membranes. The cochlea, spiral laminae, &c. then 

 niet with consideration, which parts Mr. P. conceived 

 were subservient to the diversity of sounds ; and he con- 

 cluded the human denionslration by some appropriate 

 observations on the Eustachian tube. 



The concluding part of the lecture consisted of com- 

 parative anatomical observations. All vertebral animals 

 (i. f. red-blooded animals) have an organ of hearing j it 



f C*oouiaD Lcpturc Philosophical Transaction,';, part i. 1800. 



is 



