PRESH-WATER ALGiE, 343 



has just been extinguislied, will burst iuto a flame again on 

 being immersed in any one of tliem. " I myself/^ says the 

 distinguished German chemist, ^^took an opportunity of 

 verifying this remarkable fact upon finding in a trough of 

 water in my garden the fluid coloured green by the presence 

 of various species of Infusoria. I filtered it through a very 

 fine sieve, in order to separate all Conferv<2, or vegetable 

 matters ; and then exposed it to the light of the sun in an 

 inverted broken glass, completely full, the aperture of 

 which was confined by water. After the lapse of a fort- 

 night, more than thirty cubic inches of gas had collected 

 in the glass, which proved to be very rich oxygen.''^ 



In the most extensively difi^used animalcules, then, 

 namely the green and red Infusoria, we recognize a most 

 admirable cause, which removes from water all substances 

 injurious to the life of the higher classes of animals ; and 

 creates in their place nutritive matters for the sustenance of 

 plants, and the oxygen indispensable to the respiration of 

 animals. We see, then, that the benignant purposes of God 

 towards man are answered not only by the fresh- water Algse, 

 but, what is more extraordinary and had never been sus- 

 pected till discovered by science, that the functions of 

 animal nature are reversed in the millions of millions of 



