184 THE MICROSCOPE. Dec. 



paratas, for holding the filtering paper in position, 

 lb being made and offered for sale by Chas. Lentz & Sons. 

 — Atnerican Naturalist. 



Appearance of Spontaneous Generation. 



By Dk. BOUYON. 

 Translated from Le MicrograpJie Freparafcitr by Reue Samson. 



When we bring into a narrow tube a very small pinch 

 of Algae, gathered with the end of a pole in a pond, 

 in order to examine it under the microscope, we find 

 a small number of species of animals ; then, every day, 

 we see new ones which before did not appear to be found 

 there. Thus we can, after a few weeks' research, find, in 

 a few cubic centimetres of water and a centigramme of 

 filamentous Algae almost one half of the ordinary Infuso- 

 ria. No doubt that after a longer time we could still 

 discover many others. This phenomenon is so striking, 

 when we have made the experiment, that we are tempted 

 to believe (as I have heard it taught in Paris) that all 

 Infusoria arise one from the other, under ordinary ex- 

 terior influences. It is necessary to know that Infusoria 

 are as distinct one from the other as Entomostrac^e or 

 Mollusks ; only, the same species can present natural or 

 accidental forms which have been wrongly described, by 

 the first microscopists, as so many different species. 



We understand that, the first day, we cannot see them 

 all : some species have passed unperceived ; they are 

 found again later. Besides, there are eggs, germs which 

 were not yet hatched, and which produce new species the 

 following week. And more, there often are transforma- 

 tions which require two or three weeks in which to take 

 place, and a larva which we had taken for a perfect in- 

 fusoria, can hatch and give birth at the end of twenty 

 days to a new being, which seems fallen from heaven. 



It is thus that if we observe a quantity of Oxytricha 



