108 THE ROYAL SOCIETY OF CANADA 



appeared to be dead, they revived when the temperature rose. Regnard * 

 found that carp will live in water containing 2^ per cent, of magnesium 

 sulphate, even when the temperature is a degree or two below zero; 

 at — 2° the fish appear to be asleep, and at — 3° their vitality is so grçatly 

 reduced that they seem to be dead, but revive when the water is grad- 

 ually warmed. Pictet* exhibited at one of his lectures frozen goldfish, 

 pike, and frogs, and at the next lecture the same animals alive and well 

 after gradual thawing. According to this observer, fishes can be 

 rapidly frozen so hard that they can be snapped in two, and yet other 

 fishes frozen equally hard recover when slowly thawed. It has been 

 observed by Marcet f that gold-fish completely embedded in the ice show 

 no signs of life on thawing, but one fish, which was partly encased in 

 ice and was surrounded by a little water, appeared lifeless, but recovered 

 perfectly in a short time. Observations and experiments made by 

 GaymardJ and Gavarret^ show that toads and fishes may be frozen 

 perfectly stiff and yet revive when gradually thawed; according to the 

 former observer the freezing must be gradual, otherwise the animals 

 are killed. During Franklin's explorations^ in the Arctic regions it 

 was observed that fish frozen completely hard recovered when they 

 were thawed; a carp, which had been frozen for thirty-six hours, was 

 able when it had been thawed to leap about with much vigour." 



And again (p. 823) "The eggs of silk-worms and of other insects 

 may be exposed for a long time to temperatures 20° to 30° below zero, 

 and yet will develop into larvae when removed to warm surroundings.^ 

 The Arctic explorer Ross exposed caterpillars to a temperature of — 42°, 

 and found that they recovered when slowly thawed. Colasanti^ observed 

 that hens' eggs could be exposed for two hours at a temperature of — 4°, 

 and for half an hour to a temperature of — 7° to-10°, and yet developed 

 normally when placed in an incubator." 



According to Bachmetjew' there is no minimal temperature for 

 cold-blooded animals below which continued existence is impossible. 

 The possibility of revivification, especially with hard-frozen insects, 



*Compt. rend. So3. Biol., 1895, p. 652. 



fMarcet, Croonian Lectures, Brit. Med. J., 1895, I, 1367. 



JBiblioth. Univ., Genève, 1840, 26, 207. 



* "De la chaleur produite par les êtres vivants." Paris, 1855, p. 502. 

 'Franklin, "Journey to the Polar Sea," 1819-1822, 2nd edit., Vol. II, p. 17. 

 ® Reaumur, "Mem. sur les insectes," tomes II et IV; Spellanzani, "Opusc. de 



phys. anim." tome I, pp. 82-85; Bonafous, Biblioth. univ., Geneva, 1838, tome 

 XVII, p. 200; Ross, ibid., 1836, tome III, p. 423; Pictet, Arch. sc. phys. nat., Genève, 

 1893, (3), 30, 293. 



^ Arch. f. Anat. Physiol, u. wissensch. Med., 1875, p. 477. 



* "De la température vitale minima chez les animaux dont la température du 

 sang est variable." Arch. Sc. biol. St. Petersbourg, 8, (III), 242, Zentr. f. Physiol. 

 1901, 15, 282. 



