50 MINUTE MARVELS OF NATURE 



apart, so that a hair from the human-head cut longi- 

 tudinally into 400 thin slices would approximately 

 fill the spaces between 400 of these marks. 



We cannot here even glance at the life history 



Kig. 12. Several diatom forms from the top central edge 

 of Fift, 4 immensely magnified 



and methods of reproduction of these lowly and 

 beautiful unicellular plants. The subject is so 

 great and their species are so numerous that we 

 should require a separate chapter ; so I must be 

 content to call attention to their beauties, which 

 show that the lowest and most minute forms of 

 plant life present no less wonderful intricacies of 

 structural detail than the highest and largest. 



