SPECULATIONS ON THE ORIGIN OF LIFE 311 



the origin of the totality of living beings, as known to us, was a 

 historical event which cannot be repeated on the earth unless 

 by some means all existing terrestrial life be destroyed and a 

 fresh start permitted on the tabula rasa of the earth's surface. 



But even if this conclusion be granted, the origin of life 

 would remain still a subject for investigation and experiment : 

 for if the conditions for generating new life exist in Nature, it is 

 conceivable that they can be reproduced in the laboratory ; and 

 if the only check to renewed generation of living matter in 

 Nature be the existence of specialised forms of living beings, 

 that is a check which could easily be removed in an artificial 

 environment. 



It must, however, be pointed out that all these conclusions 

 are purely speculative and hypothetical, resting upon no sure 

 basis of established fact but assuming the occurrence of pro- 

 cesses of which, as yet, we know nothing whatever. In the 

 present state of scientific knowledge, our attitude towards the 

 problem of the origin of life must be one of expectancy, of hope 

 for more light in the future. At the point at which we stand it 

 is not possible to frame any hypothesis which can have greater 

 value than that of a pious belief. Whether it will ever be 

 possible to advance beyond this point in our speculations the 

 future alone can show. 



