370 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



water at the ordinary temperature. The ou: contained salt water for 

 the salt-water fish, the other fresh water foi the silverflsh. In a short 

 time the heat of the water in the tubs found its way to the surface of 

 the ice in contact with the interior of the pannikins. The blocks, be- 

 coming iu cousequence reduced in bulk, parted, the former finding its 

 way to the bottom, the latter remaining at the surface. On examining 

 these blocks of ice it was observed that both fishes must ^ave retired 

 from the surface of the water towards the bottom during the freezing, 

 and that about half an inch of the lower part of the silverfish rested 

 on the bottom of the vessel. It must therefore have been outside the 

 ice. The other fish was entirely surrounded. The appearance of both 

 was identical. Both lay on the side, the head was higher than the tail, 

 the distended gills were filled with ice, aud the iris of the eyes had 

 neither dilated nor contracted; the aqueous humor was apparently 

 frozen. The rays of light no longer penetrated to the retina, and the 

 eyes presented the appej»rauce of balls of opaque ice. The silverfish 

 was the first to be free, and it was observed that at the moment when 

 the fin near the gill was freed from all restraint the little organ com- 

 menced to move very gently, so much so that it was impossible to say 

 but that motion was due to the parting of the ice. A few moments 

 later there was no mistake about the matter. The fish was alive. The 

 tail returned its activity. As soon as the ice had disappeared from the 

 gills, they began to open and close, and the little fish moved about 

 languidly, dreamily, groping its way. Up to this time the aqueous 

 humor of the eye had not thawed, all was darkness to the fish. It 

 seemed to be feeling its way, but soon the ice was dissolved, light en- 

 tered, and the silverfish was swimming as easily and nimbly as ever. 

 It is now alive iu a glass tank. 



The salt-water fish was gradually detached from the encircling ice^ 

 but close attention failed to notice any signs of life. When entirely 

 free it sank to the bottom dead. Perhaps the sudden contraction of the 

 water at freezing point following so rapidly upon the expansion had in 

 some way injured the fish. Obviously the air-bladder had burst, for all 

 buoyancy had departed. Why did the fish which had been taken from 

 the sunnj" waters of the Pacific but a few weeks previously survive an 

 ordeal that jiroved fatal to one fresh from the cooler waters of the 

 Waitemata? I cannot tell. 



It may yet be i)roved that fishes, which are usually classed with cold- 

 blooded animals, can survive imi»risonment in ice. Even the slight in- 

 jury caused by the fishing-hook to the salt-water fish may possibly have 

 contributed to its death. 



I frequently visited the freezing-chamber to see how the other pris- 

 oners were faring. The former two had been placed in the "shoot," 

 and consequently I bad had no opportunity of observing how they be- 

 haved as the ice gradually closed arourul them. But in the freezing- 

 chamber there was every facility for doing so. In an hour the increas- 



