68 



EAR. 



in the human species ; and are also capable of turning 

 it to any quarter from which they may be anxious to 

 collect the slightest sound. " This motion of the 

 ear," says Richerand, " is lost, or more properly 

 speaking, not employed in the human ear, as long as 

 the organ continues in a perfect state ; but when its 

 more internal mechanism is injured, and ceases to act 

 upon the sound as usual, the external ear resumes the 

 office to which it was originally adapted, and by a de- 

 gree of motion and erection assists the hearing." A 

 little distance within the hole of the ear, we come first 

 to a membrane stretching entirely across from side to 

 side, forming a complete partition. It may be com- 

 pared to the pelt or head of a drum ; and is common- 

 ly called the drum of the ear ; anatomists term it the 

 membrane of the tympanum, which means, skin of a 

 drum. Behind this partition, we come to an open 

 space usually termed the barrel of the ear, the ana- 

 tomical expression is tympanum, from a Latin word 

 signifying a drum. What is most curious to observe, 

 is the little clock work within this barrel. It is a con- 

 trivance of four extremely minute bones, one of 

 which is fastened by the end into the main drum 

 head, that is, the membrane of the tympanum, and 

 the others, connecting along from the opposite end of 

 this bone, stretch up into the barrel of the ear, till the 

 last stops upon another drum head, drawn over the 

 mouth of another barrel, which is deeply situated in 

 the solid bone of the skull, and which contains a wat- 

 ery matter, and also the nerve of the ear, floating in 

 this liquid. The second barrel, so to term it, is called 



