74 THE BIOCOSUOS PRELIMINARY. 



one and confines itself to the round of indi- 

 vidual Life. 



The second theory of the Origin of Life 

 has long been known as Spontaneous or 

 Equivocal Generation, and now goes under 

 the scientific name of Abio genesis. Here the 

 point is that Life is sometimes generated out 

 of non-vital matter. Popular belief has not 

 ceased to cling to spontaneous generation in 

 certain cases. Decayed meat is still supposed 

 to breed maggots; and horse-hairs in stag- 

 nant pools will turn to little snakes every 

 farmer-boy has seen them. Formerly many 

 scientific men, from Aristotle down, held the 

 same view. But the current began to set in 

 the other way, especially when Redi (1638) 

 showed that meat would decay without pro- 

 ducing maggots if protected from flies and 

 other insects. The newly discovered micro- 

 scope revealed a new world of infusoria 

 which were for a long time deemed to be spon- 

 taneously generated. But this position was 

 attacked, and after many experiments oft re- 

 peated with new precautions, the science of 

 to-day with a few lingering exceptions doubt- 

 less has declared itself against Spontaneous 

 Generation. It has succeeded in sterilizing 

 quite all supposed microbe-breeding liquids, 

 chiefly by boiling, as the component proto- 

 plasm enters usually into its heat-rigor below 



