USE OF THE MICROSCOPE IN ZOOLOGY. 55 



any the worse for it; indeed, they were believed to 

 be capable of resuscitation. Spallanzani has a chapter 

 with the following heading : " Animals which can be 

 killed and resuscitated at pleasure." Of course such 

 an idea is absurd; the fact, however, remains that 

 certain creatures, rotifers, tardigrade s, anguillulae, can 

 be reduced by great heat to almost thorough dryness, 

 can be kept in this condition for a length of time, and 

 yet will revive on the application of moisture. Every 

 one who is acquainted with the history of these animals 

 is aware of the experiments made on them by M. 

 Pouchet, so I shall conclude this chapter with an 

 extract -from 

 "The Uni- 

 verse" of that 

 distinguished 

 French savant: 

 " It is true we 



are, in OUr A Tardigrade. 



day, obliged to 



erase the charming romance of palingenesis, with 

 which our forefathers amused themselves. Still, we 

 must say that, although the Rotiferae cannot be resus- 

 citated when they are once dead, their tenacity of life 

 is one of the most extraordinary phenomena. Their 

 resistance to cold is something marvellous, and we do 

 not even know where it stops ; the lowest temperature 

 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. Rotiferae placed in an apparatus where 

 the temperature was 40 below zero, Centig. (40 

 Fahr.), issued from it full of vitality."* 



" The natural history of the Rotiferae is a 



* "The Universe,'.' p. 56. 



