48 Where did Life Begin? 



In the northern hemisphere was induced by a 

 Hke movement of isothermal Hnes and cH- 

 matic conditions, and while in one instance it 

 was from the south to the north, the phenom- 

 enon no more suggests, when considered in 

 connection with its exceptional and anomalous 

 causes, that the general movement has not 

 been in the opposite direction, than the fact 

 that tidal waves setting up for hundreds of 

 miles in great rivers would indicate that their 

 main currents were not always and constantly 

 to the sea. 



It hardly admits of two opinions, that or- 

 ganic life has In the main either moved from 

 the polar regions to the tropics or vice versa. 

 For, commencing in any given locality between 

 the two, and it could not have moved both 

 ways ; the temperature, climate, and other 

 conditions north and south of every locality 

 are, and must ever have been, so dissimilar 

 that if they favored a movement in one direc- 

 tion they would have forbidden it in the other. 

 Now as east and west movements are im- 

 possible, to any great extent, and as the con- 

 ditions favorable to one form of life are, as a 



