LIFE IN THE PAST 159 



interesting next to consider what the biologist sur- 

 mises as to the origin of the life upon the earth. 

 Here again two explanations hold. The one, and dis- 

 tinctly the older of the two, says that at some time 

 in the far distant past, under conditions which are 

 rarely if ever duplicated, out of the lifeless material 

 of the globe were produced simple and low forms of 

 life. These could not properly be called either animal 

 or plant, but partook somewhat of the nature of both. 

 Of this there is at present no evidence whatever. The 

 only reason we have for suggesting it is that, if we 

 understand the past conditions on the earth, there was 

 a time when life was impossible. Now we find life. 

 Hence it must have arisen. This of itself, of course, 

 furnishes no proof, but leads us to try to imagine how 

 the transition might have come about. Every scien- 

 tist who believes in this form of origin holds that if 

 the exact conditions are repeated the result will occur 

 once more. He may believe that no such repetition 

 is possible, but he is confident that, if it could be, life 

 would arise again from lifeless matter. 



This process of life arising from matter that is not 

 alive is known as Spontaneous Generation. Two hun- 

 dred years ago it was supposed to occur frequently. 

 It was common belief that the beautiful pickerel weed 

 which borders our Northern lakes, after freezing, went 

 into a sort of protoplasmic slime out of which pick- 



