156 NATURE AND LIFE. 
the blood, which is the condition of the heating, then occurs 
with much greater activity. Let us add that quite lately 
Demarquay applied this toxic action of heat on the muscles 
in the happiest manner, and without suspecting it. He 
cured patients suffering from those frightful muscular con- 
tractions which characterize tetanus, by subjecting them to 
the influence of caloric, and making them take very hot air- 
baths. The rise of temperature in the tetanized muscles 
was sufficient to modify them, and restore them toa healthy 
state. Here the poison worked a cure. 
Such are the effects on animals of the elevation of tem- 
perature. Let us now see what becomes of them when im- 
mersed in cold media. Some curious facts with respect to _ 
the freezing of certain animals have long been known. 
During his voyage to Iceland, in 1828 or 1829, Gaimard, 
having exposed in the open air a box filled with earth in 
which toads were put, opening it after a certain time, found 
the reptiles frozen, hard and brittle; but they could be re- 
stored to life when put in warm water. Many ancient au- 
thors cite similar cases, and we can almost bring ourselves 
to understand how a great English physiologist might for 
a moment have given them the whimsical interpretation 
that he did. John Hunter fancied it might be possible to 
prolong life indefinitely by placing a man in a very cold 
climate, and there subjecting him to periodical freezing. 
The man, he said, would perhaps live a thousand years, if, 
at the end of every ten years, he were frozen for a hundred, 
then thawed out at the end of the term for ten years more, 
and socontinuously. “Like all inventors,” Hunter adds, “I 
expected to make my fortune by this scheme, but an exper- 
iment completely undeceived me.” Putting carp into a 
freezing mixture, he observed, in fact, that, after being en- 
tirely frozen, they were dead, past recovery. The case is 
the same with all other animals, as the late and very re- 
markable experiments of F. A. Pouchet have proved. 
