The Theory of Evolution 43 



least, the fossils have been found in the same part of the 

 world, so that there is less risk of arranging them arbitrarily 

 in a series to fit in with the theory. 



EVIDENCE FROM DIRECT OBSERVATION AND EXPERIMENT 



Within the period of human history we do not know of a 

 single instance of the transformation of one species into 

 another one, if we apply the most rigid and extreme tests 

 used to distinguish wild species from each other. 1 It may 

 be claimed that the theory of descent is lacking, therefore, 

 in the most essential feature that it needs to place the 

 theory on a scientific basis. This must be admitted. On 

 the other hand, the absence of direct observation is not 

 fatal to the hypothesis, for several reasons. In the first 

 place, it is only within the last few hundred years that 

 an accurate record of wild animals and plants has been kept, 

 so that we do not know except for this period whether any 

 new species have appeared. Again, the chance of observing 

 the change might not be very great, especially if the change 

 were sudden. We would simply find a new species, and 

 could not state where it had come from. If, on the other 

 hand, the change were very slow, it might extend over so 

 many years that the period would be beyond the life of an 

 individual man. In only a few cases has it been possible 

 to compare ancient pictures of animals and plants with their 

 prototypes living at the present time, and it has turned out 

 in all cases that they are the same. But these have been 

 almost entirely domesticated forms, where, even if a change 

 had been found, it might have been ascribed to other fac- 

 tors. In other cases, as in the mummified remains of a few 

 Egyptian wild animals (which have also been found to be 

 exactly like the same animals living at the present day), 



1 The transformation of " smaller species," described by De Vries, will be 

 described in a later chapter. 



