02 THE MECHANICAL FUNCTIONS. 



highly developed Annelida, or worms, which 

 may be kept in a dry state for an indefinite 

 length of time, and, when moistened with water, 

 resume their activity, as if restored to life. The 

 germination of seeds under these circumstances 

 is matter of common observation ; but the revi- 

 vification of animalcules is a more curious phe- 

 nomon, for it takes place more rapidly, and is 

 more striking in its results. The Rotifer redi- 

 vivus, or wheel animalcule,* (Fig. 1 .) which was 

 first observed by Lewenhoeck, and was after- 

 wards rendered celebrated by the experiments 

 made upon it by Spallanzani, can live only in 

 water, and is commonly found in that which has 

 remained stagnant for some time in the gutters 

 of houses. But it may be deprived of this fluid, 



and reduced to perfect dryness, so that all the 

 functions of life shall be completely suspended, 

 yet without the destruction of the vital principle ; 



* Vorticella rotatoria of Gmelin, and Furcularia of Lamark. 



