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THE EUSTACH[AN TUBE. 



BY PROFESSOR' RUDINGER, 



OF MUNICH. 



THE Eustachian tube of Man and of the various species 

 of animals, is constructed on the same general plan, but in 

 different instances presents minor modifications of structure. 

 And however close may be the resemblance of the tubse of 

 various animals, the more minute differences in form they 

 present are so characteristic, that a practised observer can tell, 

 from the examination of a transverse section alone, the name 

 of the animal from which it was obtained. 



The Eustachian tube, forming a mechanical apparatus, with 

 cartilaginous and muscular tissues entering into its com- 

 position, obviously stands in intimate physiological relation 

 with the tympanic cavity. In addition to the office of carry- 

 ing off its own secretion and that of the highly vascular 

 mucous membrane of the tympanum, it is capable of effecting, 

 in consequence of its peculiar mechanism, the ventilation oi 

 this cavity. Whether the Eustachian tube plays any im- 

 portant physiological part in the conduction of sound into the 

 tympanic cavity, and whether it possesses any relations to 

 the voice of the individual, and if any, what kind of relation, 

 are questions that receive no satisfactory elucidation from 

 researches in comparative anatomy. Conclusive responses to 

 such inquiries have still to be obtained from experimental 

 investigations. 



