WHAT IS PHYSICAL LIFE 



Protozoa, which are of animal nature. 

 Second, the Bacteria, which have vegetable 

 affinities. Third, the unicellular Algse, 

 and fourth, the Foraminifera. 



Among bacteria there is no mixture or 

 crossing to anything like the degree to be 

 found among visible plants and animals, 

 but each species has its own specific char- 

 acters, making it as unlike other bacteria 

 as any two living things can be, for exam- 

 ple, a horse and a camel. A typhoid 

 bacillus can by no possibility become an 

 influenza bacillus, nor that in turn a lep- 

 rosy bacillus. Each species presents a 

 multitude of its own distinguishing feat- 

 ures, as the following facts demonstrate. 



Thus, though it may seem odd to speak 

 of size as a feature among microscopic liv- 

 ing things, yet they actually do vary in this 

 respect as much as visible forms do. The 

 bacillus of anthrax is as much larger than 

 an influenza bacillus as a cat is larger than 



