24 GENERAL HISTORY OF 



species of Polygastrica, are confined to localities more open 

 to the fresh air. Ehrenberg, for many years, has experi- 

 mented with simple spring water, with distilled water, and 

 rain water, and these both boiled and cold, as also with 

 and without vegetable matter ; that in open vessels, after 

 a longer or shorter time, depending upon temperature and 

 other circumstances, he invariably found the Infusoria ; 

 while, in closed vessels, they were rarely to be met with ; 

 so that, I think, we may consider generatio aquivoca, even 

 in Infusoria, as an unphilosophical hypothesis ; and that 

 the same fixed laws of Creative Wisdom, which regulates 

 and governs the smallest satellite and the largest starry 

 world through boundless space, has established the same 

 law for the developement of a living atom, as is manifested 

 to us in the largest animal that inhabits this planet. 



SECTION V. On the Method of Capturing, Selecting) and 

 Placing Infusoria for Examination under the Microscope. 



Having provided yourself with a number of clean glass 

 wide -mouthed phials those containing about four ounces 

 a piece will be found most suitable let them be fitted with 

 proper corks, and not with glass stoppers. If it be required 

 to have all the tackle neatly arranged, they maybe put into 

 a small case, expressly constructed for the purpose, and each 

 bottle separately marked. In place of phials, however, 

 cylindrical glass vessels, from three to five inches long, 

 may be substituted with advantage, as they will lay better 

 in the case, which need not exceed . the dimensions of a 

 common sandwich -box. A good walking-stick, with a 



