166 OF HEARING. 



254. Besides the muscles of the malleus and 

 stapes,* supposed to be voluntary, f the chorda tym- 

 pani, J which is placed between the handle of the malleus 

 and the longer leg of the incus, is believed to moderate 

 the force of sound that is struck against the membrana 

 tympani and intended to be propagated along the cavity 

 of the tympanum. (B) 



NOTES. 



(A) The cerumen consists, according to Vauquelin, of al- 

 bumen, which, when burnt, yields soda and phosphate of lime, 

 a colouring matter, and a very bitter inspissated oil strongly 

 resembling the peculiar matter of bile. Cicero, that prodigy of 

 genius, knowledge, and goodness, explains one use of the 

 cerumen : " Provisum etiam, ut, si qua minima bestiola cona- 

 retur irrumpere, in sordibus aurium, tanquam in visco, inlueres- 

 ceret." || The same applies to particles of dust. Its extreme 

 bitterness too deters insects from advancing. Its chief purpose 

 is probably to preserve the passage in a fit state for conveying 

 vibrations : a flute is useless if perfectly dry. 



(B) There was an old opinion which appears to my mind 



* B. S. Albinus, Tabula; Muscul. tab. xi. fig. 29. 



f Eustachius, DC Auditus Organ, p. 157. 



Caldani, Institut. Physiol. 245 sq. 



J J. Fr. Meckel, De Quinto pare Nervorum Cerebri. fig. 1. x. 71. 



Lcop, M. A. Caldani on the office of the chorda tyinpani, Saggi dell' Acad. 

 di Pud'i'ja. T. ii. 



Cotunni, 1. c. Ixxxviii. Marhcrr, Preelect. in Boerhaavii Inst. Vol. iii. 

 p. 343. 



|| DC Natura Deorwn. L. ii. 



