AND OTHER WARM BLOODED ANIMALS. 8-'50 



man, from a state of suspended animation, is 

 much greater than is generally supposed. At 

 the same time, there is reason to believe, that 

 this power is confined to cases in which there has 

 been no serious disorganization, that when the 

 movements of life are suddenly arrested from any 

 cause, the blood undergoes the process of co- 

 agulation, or is so far disorganized as to become 

 unfit for nutrition, for we have seen that when 

 taken from a healthy sheep, and surrounded by 

 a freezing mixture at 0, it coagulated before con- 

 gealing. Owing, however, to the gradual reduc- 

 tion of their temperature, circulation, &c. on the 

 approach of winter, the blood of reptiles and hy- 

 bernating animals does not coagulate ; so that on 

 the return of spring it recovers its fluidity, colour, 

 and power of stimulating the heart and other 

 organs, at the same time. I have shown that 

 after blood has been frozen, its contractility, like 

 that of the muscular fibre, may be restored by 

 raising its temperature. But that its organiza- 

 tion may be seriously deranged by congelation, 

 would appear from the fact, that after eggs have 

 been frozen and then thawed, they lose their 

 transparency, and become opaque, (as may be 

 seen by holding them up to the light,) and will 

 not hatch. 



In attempting to restore suspended animation, 

 it is idle to rely on electricity, bleeding, injec- 

 tions of tobacco, and other equally useless or per- 



31 



