138 FISH HATCHmO. 



contained in it, by the action of the jgills of 

 the fish — is intimately connected with the 

 involuntary principle by which all organs 

 engaged in the carrying on of life are 

 actuated. 



Having obtained from Mr. Buckland (2nd 

 Life Guards), and from Mr. Bartlett, of the 

 Zoological Society's Menagerie, some young 

 salmon and trout, I proceeded to the inves- 

 tigation by, in the first place, submitting 

 a living fish to the microscope, employing 

 for the purpose a 2-inch object glass. 

 Under this power the muscle could be 

 seen distinctly contracting and expanding 

 as it opened the mouth of the fish and 

 moved the pectoral fin. Having thus as- 

 certained the exact position of the muscle, 

 I proceeded to take a dead .fish, and dis- 



