DIFFUSION OF LIVING BEINGS. 19 



glasses of considerable size, but now achromatic 

 lenses vary from two inches to a twelfth or six- 

 teenth of an inch focal length. The Microscopical 

 Society of London was expressly formed to render 

 this instrument still more available for scientific 

 research. 



Wherever we turn whether we search our own 

 dwellings, the meadow or the moorland, the hill or 

 the forest, the ruin crumbling into dust, or the sea- 

 shore, whether we examine the waters of springs, 

 rivers, lakes, or oceans, or the fluid contents of the 

 living internal tissues, there may be discovered 

 plants and animals, alike unknown to our unaided 

 vision, yet endowed with organs perfectly adapted 

 to their respective necessities, and, with regard to 

 the latter, to their full and high enjoyment. Even 

 in the aqueous vapours, and dust of the atmosphere, 

 are germs of living beings, which the microscope 

 can alone present to our interested and delighted 

 contemplation. Of this the succeeding pages of this 

 volume will afford ample evidence. 



