70 THE EUSTACHIAN TUBE, BY PROFESSOR RUDINGER. 



tissue surrounding the cartilage consists of alternate layers of 

 connective tissue and elastic fibres. In Felis domestica, Felis 

 leo, and Felis tigris, the cartilage is essentially limited to a 

 hook at the end of the tubal fissure. The remaining portion 

 of the tuba of these animals is enclosed by dense fibrous tissue, 

 containing small lamellae of cartilage on its median side. 



I once saw a large amount of fat infiltrated into the tubal 

 cartilage of Man, conferring an unusual appearance upon it, by 

 rendering it two or three times larger than natural in all its 

 dimensions ; both cartilages projected to a considerable extent 

 from the wall of the pharynx. 



2. THE MUSCULAR (MEMBRANOUS) SEGMENT. 



I have already had an opportunity of remarking that the 

 expression, " membranous portion of the tube," is very indeter- 

 minate. It immediately suggests the mucous membrane to 

 the mind, which however by no means belongs to one segment 

 of the Eustachian tube alone, but lines this throughout its 

 whole extent, and is connected both with the cartilage and 

 with the muscles. If the expression is to be used, it should 

 be understood to indicate that part of the tube which is not 

 invested by cartilage, and there is then no objection to its use, 

 since these two parts can be demonstrated in the Eustachian 

 tube of many animals. 



In the meanwhile, though disposed in general to be exceed- 

 ingly precise in reference to nomenclature, we still think it 

 may be found advantageous for Man and many animals to 

 give up the term at present in use, and to name the segment 

 of the tuba in question the " muscular segment!' 



I am well aware that muscles are here present which do not 

 exclusively belong to the tuba, and that this term does not 

 express the complete morphological characters of the segment 

 of the Eustachian tube in question. No absolute necessity, 

 however, exists that all the characteristic features should be 

 expressed in the nomenclature, and it appears to me that it 

 will be convenient to derive the name of this segment from 

 the muscles which both morphologically and physiologically 

 stand in such intimate relation with it. 



