THE PHVSTCAL BASIS OF LIFE 



15 



breath. Such i-csidts arc indeed staggering — to a certain 

 type of mind even harder to assimilate than those which 

 physicists are now asking us to accept concerning the 

 structure of atoms. Xevcrtltcless they are prohahJij true! 



Let me emphasize tlie fact that these conclusions are 

 not a pi'oduct of the seventeentli century but of the 

 twentieth. Tliev did not arise in the fertile imagination of 





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FIG. 6 

 Structure of the uiielear threads from oocytes of the flat-worm Dendrocoelum 

 (from Gelei). The threads are longitudinally divided and show in each case a 

 double series of smaller bodies or chromonieres. 



a Bonnet, a Butfon or a Weismann. They were the out- 

 come of accurate and extended experiments under care- 

 fully controlled conditions; they make possible precise 

 quantitative prediction concerning the outcome of new 

 experiments. In these respects they are employed in the 

 same way as the exact concepts of the chemist or the 

 physicist and they may, I think, lay claim to a A'alidity of 

 the same kind even if it be not yet (piite of the same de- 

 gree. It is theoretically possible, I suppose, to consider 



