132 FISH HATCHING. 



of the salmon wlien it was under the glass, 

 and ascertained that it averaged about 

 seyenty in a minute. My friend, Mr. Hall, 

 of Farningham, has made observations on 

 the pulse of one of his young trout. He 

 reports that, on April 6 th, when the fish 

 was just hatched out of the ovum, the pulse 

 was eighty per minute. On the 13th it was 

 ninety-five, and on the 1 7th, one hundred-and- 

 twelve per minute. Just below the heart can 

 be seen on the umbilical vesicle (when the 

 fish is in the water) a bright red streak ; 

 examine this under the microscope, and you 

 will see that this red streak is in fact a main 

 artery ; with a high power, you can see 

 plainly the minute blood-discs coursing along 

 between the walls of this elastic tube. The 

 minor red streaks upon, the umbilical yesicle 



