THE BEGINNINGS OF LIFE 



well have seemed possible for animalcules to be 

 spontaneously generated in air-tight flasks, or 

 even for maggots to arise de novo in decaying 

 meat. Such a view might have been logically 

 defensible, though it was not the one which 

 actually prevailed. But now, in face of the proved 

 fact that thousands of years are required to ef- 

 fect any considerable modification in the specific 

 structures of plants and animals, it has become 

 impossible to admit that such specific structures 

 can have been acquired in a moment, or other- 

 wise than by the slow accumulation of minute 

 peculiarities. Hence " spontaneous generation " 

 can be theoretically admitted only in the case of 

 living things whose grade of composition is so 

 low that their mode of formation from a liquid 

 solution may be regarded as strictly analogous 

 to that of crystals. And when the case is thus 

 stated, it becomes obvious that the phrase "spon- 

 taneous generation " is antiquated, inaccurate, 

 and misleading. It describes well enough the 

 crude hypothesis that insects might be gener- 

 ated in putrefying substances without any as- 

 signable cause ; but it is not applicable to the 

 hypothesis that specks of living protoplasm may 

 be, as it were, precipitated from a solution con- 

 taining the not-living ingredients of protoplasm. 

 If such an origination of life can be proved, 

 none will maintain that it is " spontaneous," 

 since all will regard as the assignable cause the 

 3Si 



