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26. — Fisn-HATCHixG AND FisH-crxTURE i^' Hert^-oedshiee. 



By Alfred T. Brett, M.D. 



With. Notes on Pisciculture, by Peter Hood, M.D. 



[Read 11th January, 1877.] 



The science and art of Pisciculture is so interesting and so 

 important that I have ventured to bring it before the notice of our 

 Society. 



The interest of the subject is evident whether we regard it as 

 naturalists, as physiologists, or as political economists. It affords 

 great pleasure to the student of nature to observe the instincts and 

 habits of fish during the breeding season ; how the fish when she 

 wishes to lay her eggs fii'st proceeds to make the nest for them, 

 " salmon and trout making use of stones for this puipose ; other 

 fish, especially sea-fish, making use of vegetable material, either, 

 as in the case of the stickle-back, building a true nest, or else 

 depositing the eggs upon the fronds and leaves of plants." 



To the physiologist the study of the young fish is full of interest. 

 Mr. Frank Buckland says : — " Get out the microscope 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, 

 propelling the blood to all parts of the body. . . . Again, down 

 the centre of the transparent body of the fish can be seen, with the 

 unassisted eye, two tiny streaks. The microscope shows that these 

 also are blood-vessels, and that the blood in one is running towards 

 the heart, and in the other towards the tail. A more complete and 

 beautiful demonstration of the circulation of the blood never was 

 yet placed under a microscope."*' 



I will not detain you with other examples of the facts to be 

 learnt from the study of new-born fish. To watch the gradual 

 development of that mysterious something we call life excites in 

 us wonder and great interest. 



For the political economist fish-culture is of great national im- 

 portance. For if, as it has been well said, he deserves well of his 

 country who makes two blades of grass grow where one grew before, 

 I think he desei-ves great praise who makes ten fish swim where 

 one swam before. Here then, as Lord Essex once said, " is a 

 mine of wealth under water, as much as under ground ; " and if 

 for a moment you look at a map of the globe, you will see that 

 about three-fourths of the whole earth is covered by water. But 



* Fish-Hatching-, pp. 131, 133. 



