294r Prof. Guthrie^ LL,B. — Oil the Subjective Causes of Evolution ^^c. 



impossible. As already observed, in tbe boundless field of the infinitely- 

 little there are infinite possibilities. The doctrine of spontaneous 

 generation has never been disproved, and probably never can be dis- 

 proved, though the too hasty conclusions of some physicists who have 

 claimed to produce the necessary conditions for the passage from the 

 inorganic to the organic forms have been successfully disproved. 



To summarise these results, it may be said that the hypotheses of 

 the supernatural creation of organic life, or of its perpetual existence 

 on the Earth, throw no light on its subsequent evolution, but the 

 hypotheses of the introduction of organic life by migration or spon- 

 taneous generation seem inevitably to lead to the conclusion that life 

 has originated on the Earth, not as Darwin supposes from one or a 

 dozen ancestors, but that the process of life introduction is one that is 

 continually going on, or at any rate must have happened a countless 

 number of times. Whether the forms of life thus introduced are 

 countless is another question. If it be permitted us to reason about 

 matter so entirely beyond our experience, we might infer from analogy 

 that the process of what may be called organic crystallization is 

 possible in only a limited number of ways so that the number of forms 

 produced by spontaneous generation, if such generation exists, would 

 be comparatively few. If the migration theory be true, then on the 

 other hand there would seem to be no limit to the number of forms 

 that might be introduced. 



If the migration theory be maintained then the Darwinian 

 hypothesis may be sufficient by itself to account for the present state 

 of terrestrial organic life, since the immigrant forms may have brought 

 with tliem the hereditary tendency to vary in specific lines. 



If, however, the doctrine of spontaneous generation be maintained, 

 then we seem compelled to supplement Darwin's hereditary tendency 

 to specific variation by Lamark's theory of a purely subjective 

 tendency to specific variations, supplemented by Darwin's theory as to 

 ihe objective control of such subjective tendency ; but, whether we 

 accept Darivin's, theory alone or use it as a supplement to Lamark's, 

 whether on account of heredity or on account of heredity and 

 subjective law combined, we are driven to the conclusion that the 

 tendency is to variation in specific directions^ and consequently to 

 the independent origination of the sayne varieties, and therefore of 

 the same species and genera, so that independent simultaneous 

 \variation must be admitted as a vera causa for the existence of ivide-^ 

 spread species. 



