THE ANIMAL KINGDOM. 51 



But, on the other hand, those men who have made them- 

 selves illustrious by their immortal labors with the micro- 

 scope, such as Ehrenberg and Diesing, reduced this hypoth- 

 esis to nullity. The former, in a communication to me, 

 with one stroke of his pen, characterized the error of the 

 philosophers whom we are opposing. " They only resusci- 

 tate," he said, "animals which are not dead.''' 



But although belief in revivification has vanished in the 

 presence of reason and experiment, it must be admitted 

 that there were a host of extraordinary circumstances, which 

 were quite calculated to mislead men's minds very easily 

 indeed. 



It is true we are, in our day, obliged to erase the charm- 

 ing romance of palingenesis, with which our forefathers 

 amused themselves. Still we must say that, although the 

 Rotifera cannot be resuscitated when they are once dead, 

 their tenacity of life is one of the most extraordinary phe- 

 nomena. Their resistance to cold is something marvellous, 

 and we don't even know where it stops ; the lowest temper- 

 ature that we can obtain in our laboratories does not seem 

 to have any effect upon them. I have seen these animals 

 defy a cold which would kill a man a hundred times over. 

 Rotifera placed in an apparatus where the temperature was 

 40 Fahr. issued from it full of vitality. 



The natural history of the Rotifera is a marvel from be- 

 ginning to end. I have sometimes removed them quickly 

 from the freezing apparatus and thrown them into a stove 

 heated to 176 Fahr. When they emerged from this, on 

 being immersed in water they were seen to recover their 

 animation and run about full of life. In this twofold test 



