Chap. XX.] THE AMCEBA. 359 



conditions attainable in our biological laboratories. Let us be 

 careful, however, not to dogmatise on this subject. Whether 

 living forms ever spring from not-living matter, in ponds or in 

 the great ocean, we do not know. Nor do we know whether 

 abiogenesis has or has not taken place in times geologically 

 remote. 



