-1859] WHITINGS OF JOSEPH HENRY. 209 



stances ; and a reduction of temperature by the application 

 of external cold produces, as is well known, a sluggish con- 

 dition, which finally terminates in death. The effect of 

 external cold can be prevented by artificial covering, or it 

 may be obviated, in the case of domestic animals, by an 

 extra allowance of food. The sagacious farmer is aware of 

 the fact that a well-sheltered enclosure for cattle is not only 

 a humane but an economical provision. 



Many observations have been made on the temperature 

 peculiar to different animals, and a considerable number of 

 observations recorded of a less scientific character in regard 

 to the effect of the variations of temperature to which they 

 may be subjected without permanent injury. The most 

 astonishing fact, and one which could scarcely be believed 

 if we were not in this country familar with it, is that many 

 cold-blooded animals can be actually frozen, and be to all 

 appearance dead, and j^et be revivified by gradually thawing 

 in water near the freezing point. 



Fish, as we are assured on credible authority, are often 

 brought to our northern markets from a great distance in a 

 frozen condition, and may be restored to life by the process 

 we have mentioned. 



This is a subject, as it appears to me, of high interest in 

 a physiological point of view, and would richly repay the 

 application of well-devised systems of investigation. Can it 

 be possible that the animal is frozen entirely through, and 

 that every vital act is suspended ? To what degree can a 

 like result be produced on warm-blooded animals, and how 

 far can the state of hibernation be prolonged without death 

 to the individual? Will it ever be possible, in the case of 

 any of the higher mammalia to so maintain the unstable 

 equilibrium of constitution as to prevent decay, and at the 

 same time to preserve in a latent state the vivifying prin- 

 ciple? Though investigations on this point would be inter- 

 esting we can scarcely hope to realize from them one of the 

 fancies of Dr. Franklin, that of sending representatives of 

 one age down to another to keep alive more actively the 

 sympathies of the present with the past. 



14-2 



