The Message of Science. 21 



that which first stirred on the early shores of the azoic 

 oceans. 



As the student examines those wonderful little integers, 

 the " cells," day by day, the inquiry constantly presents 

 itself, Why does the living matter adopt this form ? Why 

 does it live in these little globules of uniform size ? for 

 although the size of cells differs considerably relatively to 

 each other in different tissues and situations, the difference 

 is mainly within certain definite limits ; and the general 

 type and form are unmistakable and apparently un- 

 changeable. 



Why does protoplasm exist in such small measures of 

 substance, each scarcely more than a pin's point? Why 

 do its " cells " fail, since they are constantly growing, to 

 attain larger size, an inch or more in diameter? Why do 

 they not coalesce in the tissues into one sentient working 

 mass? And why, on the contrary, do they constantly 

 divide, when these small dimensions are reached, and be- 

 come dormant, die even, rather than transgress them? 

 These are inquiries which the student will find often re- 

 curring as he observes cell life. The idea conveyed from 

 the totality of such questionings is one of a certain ever- 

 present barrier to protoplasmic life, or a constantly re- 

 stricting law which makes life on the earth possible only 

 in this small form, or type. Some stress of terrestrial 

 matter appears to confine life to this minute expression. 

 This little cell is the only way in which life upwells 



