MICROSCOPIC APPEAEANCES. 131 



MICEOSCOPIC APPEAEANCES OF YOUNG FISH. 



Let us now see if we cannot learn more 

 about the young fish. 1 Get out the micro- 

 scope, and place a young, new-born salmon 

 under a low power, and you shall see one of 

 the most beautiful sights ever beheld by 

 human eye. You shall see the tiny heart, 

 which is situate just underneath the lower 

 jaw, going pit-a-pat, pit-a-pat ; you shall see 

 the blood at one instant in one cavity of the 

 heart (where it appears like a red speck) ; at 

 the next instant it is in the other side of the 

 heart ; and so it goes on, day and night, 

 never ceasing, never tired — a great forcing- 

 pump, propelUng the blood to aU parts of the 

 body, and gradually building up the frame of 

 a future king of fishes. I counted the pulse 



K 2 



