5 2 FREEZING BIOPLASM. 



are placed, for their means of evolving internal heat 

 are so slight and imperfect, that these may be left out 

 of consideration altogether. Their bioplasm or living 

 matter is adapted to live and grow at very low tem- 

 peratures. Some organisms which do not grow and 

 flourish at a temperature much below 50* are never- 

 theless capable of bearing a low temperature, and 

 may even live for a length of time imprisoned in solid 

 ice. Whether the bioplasm of their organism is 

 actually frozen is very doubtful. It is more likely 

 that the bioplasm resists for a long time the process 

 of congelation, and it seems to me probable that the 

 motion which there is reason to think continues during 

 life, prevents the living matter from freezing. Death 

 most likely occurs before congelation takes place, but 

 when once the living matter has actually become 

 ice, its life is for ever destroyed, and it is inca- 

 pable of being revivified or revitalized. It can never 

 live or move again. 



With regard to the power possessed by certain living 

 organismsof resisting the destructive influence of a high 

 temperature, it must be remarked that of certain of 

 the forms discovered in the closed vessels (see p. 47), 

 little is yet known. Many have been passed over by 

 highly distinguished observers, and it is even probable 

 that some have altogether escaped notice up to this 

 very time. Of the very minute organisms in question, 

 some may be able to resist the degree of heat to 

 which they are exposed in the course of the experi- 



