MICRO-ORGANISMS 

 to thirty minutes, but he can have 17,000,- 

 000 descendants in twenty-four hours.* 

 Now, estimating the life only of an elderly 

 tubercle bacillus at thirty minutes, and 

 then calculating how many generations he 

 goes through in the three thousand years 

 since we have made his acquaintance, he 

 has traced his descent through 5,450,000 

 generations, without once deviating from 

 the venerable type with which he began. 

 This only illustrates afresh what a complex 

 and absolutely unique thing life is. When 

 lately a new star suddenly flashed in the 

 heavens and after a time faded away, 

 astronomers agreed that the origin of this 

 latest " Nova " was from the collision of 

 separate stars or of streams of meteorites, 

 which, judging by the rate at which light 

 travels, probably took place while Sol- 

 omon's Temple was in building. But the 

 problem of the origin of a star is simple 



* Muir and Ritchie, Manual of Bacteriology, p. 6. 



