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THE 



AQUARIUM 



The Transportation of Live Fish in 

 a Frozen Condition 



Fishes I)eloiig to the class of animals 

 that have variable body temperature, de- 

 pending on the temperature of their en- 

 vironment. In extreme cold they assume 

 a rigid condition, in which all of the 

 vital functions are suspended, while life 

 still remains present. During several 

 months of each year some of the great 

 rivers of Siberia are frozen solid to the 

 bottom, but many of the fishes impris- 

 oned in the ice retain their vitality and 

 resume their active life when the ice 

 melts in spring. 



This fact has suggested experiments in 

 the freezing of live fish for transporta- 

 tion, which are discussed in the Fischcrci 

 Zeitung. Many years ago the celebrated 

 physicist Pictet of Geneva put fresh wa- 

 ter fishes into a tub of water, which he 

 kept liquid at the freezing point for '^4 

 hours, and then allowed to freeze slowly 

 into a solid block of ice, which after- 

 ward was cooled gradually to — 20 deg. 

 Cent. ( — 4 deg. Fahr.). When the ice 

 was melted a month or even two months 

 afterward, the fishes began to swim as 

 briskly as they did before freezing, and 

 showed no symptom of ill health. 



Similar experiments have recently 

 been made in France. The fishes are 

 placed in water which is kept near the 

 freezing point for a few hours, then at 

 the freezing point for 1 --) to IS hours, and 

 finally frozen by immersing the vessel 

 into a freezing mixture, producing a 

 cake of ice a few inches thick, in which 

 the frozen fishes are imbedded. This 

 cake is wrapped in cloth and surrounded 

 with a heat-insulating packing, to pre- 

 vent melting during transportation. It 



is necessary to thaw the ice very slowly 

 and to keep the water near the freezing 

 point for several hours, in order to pre- 

 serve the life of the fishes. Even those 

 which do not survive are in a perfect 

 state of preservation. 



In the markets of Irkutsk, Siberia, fish 

 are displayed for sale in the frozen state 

 piled up like cordwood. Fish in cold 

 storage are preserved frozen in slabs of 

 ice. The latter method is now applied in 

 the shipment of live fish. The method 

 of shipping live fish in water is not feasi- 

 ble on account of the expense, as from 

 1 to 1 gallons of water are required for 

 each pound of fish, according to the va- 

 riety. Since the discovery by Pictet that 

 fish may be frozen in blocks of ice with- 

 out being killed, and that they will be- 

 come as lively as ever after they are 

 thawed out, a method has been devised 

 for preparing them for shipment in ice. 

 The method is described in the Scientific 

 American. The fish in a large amount 

 of water are placed in a closed tank, and 

 oxygen under pressure is supplied. The 

 greater portion of the water is then 

 drawn ofi". The fish remain in good con- 

 dition on account of the abundant sup- 

 ply of oxygen. The vessel containing the 

 fish is then placed in a freezing tank and 

 the fish are frozen into the ice formed. 

 The blocks of ice containing the fish can 

 then be jiiled up in the ordinarv refrig- 

 erator car. On arrival at their destina- 

 tion the fish are ])ut through a slow 

 thawing process lasting ten hours, when 

 they return to their normal state of ac- 

 tive animation. 



The fishing line will soon be the pop- 

 ula r chord. 



