NON-MATHEMATICAL SCIENCES 177 



By scrutinizing these crystals we may pick 

 out, as Pasteur did, the one kind or the other, 

 and thus obtain a right- or left-handed sub- 

 stance; but this is an exercise of conscious 

 choice on our part. Now it is of the greatest 

 interest to observe that not only we ourselves 

 but other living things are capable of sepa- 

 rating the right- and left-handed substances. 

 While their separation in the inanimate world 

 would be an extraordinary occurrence, in the 

 world of animate nature it is the rule and not 

 the exception. There is probably not a single 

 living cell which does not contain thousands of 

 optically active substances, and this is one of 

 the most striking attributes of living things. 



The whole complex field of organic chemistry 

 is chiefly due to vital processes. Of course the 

 old sharp distinction between inorganic chemis- 

 try and the chemistry of living tissues went the 

 way of all such distinctions when Wohler dis- 

 covered that a typical organic substance could 

 be S3'nthesized in the laboratory. But after all 

 Wohler was a living being and merely produced 

 outside of himself what other men produce in- 

 side themselves. If one could only know this 

 world as it would have been without the inter- 

 vention of men and microbes, he would not even 



