110 SALMONIA. 



which occasion constant contractions and ex- 

 pansions, or openings and closings of this 

 membrane, and the life of the fish is de- 

 pendant on the process, in the same manner 

 as that of a quadruped is on inspiring and ex- 

 piring air. When a fish is hooked in the 

 upper part of the mouth by the strength of 

 the rod applied as a lever to the line, it is 

 scarcely possible for him to open the gills as 

 long as this force is exerted, particularly when 

 he is moving in a rapid stream ; and when he 

 is hooked in the lower jaw, his mouth is kept 

 closed by the same application of the strength 

 of the rod, so that no aerated water can be 

 inspired. Under these circumstances he is 

 quickly deprived of his vital forces, particu- 

 larly when he exhausts his strength by moving 

 in a rapid stream. A fish, hooked in a part 

 of the mouth where the force of the rod will 

 render his efforts to respire unav?iling, is much 

 in the same state as that of a deer caught 

 round the neck by the lasso of a South Ame- 

 rican peon, who gallops forwards, dragging 

 his victim after him, which is killed by strangu- 

 lation in a very short time. When fishes are 



