Heath. — On the Effect of Cold on Fishes. 277 



water towards the bottom during the process of congelation, and that about 

 half an inch of the lower part of the silver fish had actually rested on the 

 bottom of the vessel, and must therefore have been outside the ice. The 

 other fish was entirely surrounded. The appearance of each was identical, 

 they both lay on their side, the head was higher than the tail, the distended 

 gills were filled with ice, and the iris of the eyes had neither dilated nor 

 contracted but the aqueous humour was apparently frozen. The rays of 

 light no longer penetrated to the retinas, and the eyes presented the appear- 

 ance of balls of opaque ice. It was an anxious time to those gentlemen who 

 joined me in watching the interesting prisoners as they came out from their 

 icy shroud. The silver fish 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 commenced to move gently, very gently, so much so that 

 it was impossible to say whether the movement motion was due to the 

 parting of the ice, or to the action of the muscles of the animal. A few 

 moments afterwards, however, there was no mistake about the matter, the 

 fish tvas alive. The tail awoke to its usual activity, and, as soon as the ice 

 had disappeared from the gills, they began to open and close, and the little 

 fish moved about in the water languidly, dreamily, and to all appearance 

 groping its way. Up to this time the aqueous humour of the eyes had not 

 thawed, all was darkness to the fish, which seemed to be literally feeling its 

 way, but soon the ice was dissolved, light entered, and the silverfish in a 

 very short time was swimming as easily and nimbly as it now does in a 

 glass globe in my house. Meantime, the salt-water fish was being steadily 

 detached from the encircling ice, but the most watchful attention failed to 

 notice any signs of returning life. When entirely free it sank to the bottom 

 — dead. Perhaps the sudden contraction of the water at freezing point fol- 

 lowing so rapidly upon the expansion had in some way injured the fish, 

 obviously the air-bladder had burst, for all buoyancy had departed. I 

 cannot answer the question, " Why did the animal, which had been taken 

 from the sunny waters of the Pacific but a few weeks previously survive an or- 

 deal that proved fatal to one fresh from the cooler waters of the Waitemata ?" 

 A more extended and more efficient series of experiments may yet prove 

 that, after all, the fish, which is usually classed among the cold-blooded 

 animals, may survive imprisonment in ice. It has been suggested that 

 even the slight injury caused by the fishing hook to the salt-water fish may 

 have contributed to its death, but hypothesis is of small value in a case of 

 this kind, unless it leads us to absolutely indisputable facts. 



During the day I paid frequent visits to the freezing chamber to see how 

 the other prisoners were faring. The former two had been placed in the 

 " shoot," and consequently I had had no opportunity of observing how they 



