ORGANIC MECHANISM. 63 



for this atom of dust, after remaining for years in 

 a dry state, may be revived in a few minutes by 

 being again supplied with water. This alternate 

 suspension and restoration of life may be re- 

 peated, without apparent injury to the animal- 

 cule, for a great number of times. Similar 

 phenomena are presented by the Vibrio tritici, 

 (Fig. 2.) or the animalcule, resembling an eel in 

 its shape, which infests diseased wheat, and 

 which, when dried, appears in the form of a fine 

 powder : on being moistened, it soon resumes its 

 living and active state.* The Gordius aquaticus, 

 or hair worm, which inhabits stagnant pools, 

 and which remains in a dry, and apparently 

 lifeless state when the pond is evaporated, will, 

 in like manner, revive, in a very short time, on 

 being again immersed in water. The same phe- 

 nomenon is exhibited by the Filaria, a thread- 

 like parasitic worm, infesting the cornea of the 

 eye of the horse, f 



Both the composition of the fluid and the 

 texture of the solid parts of animal and vege- 

 table bodies are infinitely varied, according to 

 the purposes they are designed to serve in the 

 economy. Scarcely any part is perfectly homo- 

 geneous ; that is, composed throughout of a single 

 uniform material. Few of the fluids are entirely 



* See a paper on this subject by Mr. Bauer, Phil. Trans, for 

 1823, p. 1. 

 t Blainville, Annales des Sciences Naturelles; X. 104. 



