138 THE BEGINNINGS OF IIFE. 



tendency to combine, and in both cases the products 

 of combination are insoluble — particles of crystalline 

 matter appear in the one case, and particles of living 

 matter in the other. But the living matter differs 

 essentially from the crystalline matter by reason of 

 the complexity of its constituent molecules, and their 

 constant tendency to undergo small variations in com- 

 position or minute relative rearrangements. This 

 capacity for intestine molecular movement, which is 

 one of the most distinctive attributes of living matter, 

 might well be most marked in the products which 

 separate from the most fermentable solutions j and it 

 is precisely this attribute which is the principal factor 

 in bringing about the self-multiplication, or discon- 

 tinuous growth, of living units. 



Thus it is that rapid growth and rapid fission fre- 

 quently go on simultaneously j so that although the 

 total amount of living matter which separates from 

 the solution may be large, the individual living units 

 are very small. ^Discontinuous' growth is in excess, 

 and therefore the fact of the growth being really rapid 

 is apt to be overlooked. 



All the differences in size and form recognizable 

 between small Bacteria and large Bacteria i between 

 the latter and Vihriones^ whether jointed or unjointed ; 

 between Vihrio-nes and Leptotkrix filaments, plain or 

 segmented in various ways; and between Leptotkrix 

 and mycelial filaments of a Fungus^ are easily explicable 

 in accordance with these considerations. The several 



