INCREASE OF ANIMALCULES. 137 



developed, and to assume their due form and situation. 

 And as to productiveness, the Paramecium aurelia, 

 well supplied with food, has been observed to divide 

 once in twenty-four hours, so that, as professor 

 Jones observes, "in a fortnight, allowing the pro- 

 duct of each division to multiply at the same rate, 

 16,384 animalcules would be produced from the 

 same stock," and in four weeks, the astonishing 

 number of 268,435,456 new and distinct beings. 



The question arises, from this astounding in- 

 creaseto what is it attributable ? Various replies 

 have been offered to it, but the only satisfactory 

 one is, " from the air," in which the germs of these 

 beings are borne hither and thither, and under 

 certain circumstances become visible. The follow- 

 ing experiments will leave the reader in no doubt 

 on this point. A very intelligent and careful ob- 

 server says, " I filled a glass flask half full of dis- 

 tilled water, in which I mixed various animal and 

 vegetable substances ; I then closed it with a good 

 cork, through which I passed two glass tubes, bent 

 at right angles, the whole being air-tight. It was 

 next placed in a sand bath, and heated until the 

 water boiled violently, and thus all parts had reached 

 a temperature of 212 Fahrenheit. While the watery 

 vapour was escaping by the glass tubes, I fastened 

 at each end an apparatus, which chemists employ for 

 collecting carbonic acid ; that to the left was filled 

 with concentrated sulphuric acid, and the other with 

 a solution of potash. By means of the boiling heat, 



