442 COSMIG PHILOSOPHY. pt. il 



regions of mythology, where it may continue to satisfy tlioso 

 to whom mythologio interpretations of natural phenomena 

 still seem admissible, but can hardly be deemed of much 

 account by the scientific inquirer. 



On the other hand, according to the doctrine of derivation, 

 the more complex plants and animals are the slowly modified 

 descendants of less complex plants and animals, and these in 

 turn were the slowly modified descendants of still less com- 

 plex plants and animals, and so on until we converge to those 

 primitive organisms which are not definable either as animal 

 or as vegetal, but which in their lowest forms are mere shreds 

 of jelly-like protoplasm, such as the spontaneous combination 

 of colloidal clusters of organic molecules might well be 

 capable of originating under appropriate conditions, after the 

 manner pointed out in the preceding chapter. The agencies 

 by which this slow derivation of higher from lower forms has 

 been effected are agencies such as are daily seen in opera- 

 tion about us ; namely, individual variation, adaptation to 

 environing circumstances, and hereditary transmission of in- 

 dividual peculiarities. Obviously such a hypothesis is not 

 only highly credible in itself, since it only alleges that the 

 growth of a complex organism from a simple globule of 

 protoplasm, which is accomplished in every case of individual 

 evolution, has also been accomplished during the evolution 

 of an immensely long series of individuals ; but it is also a 

 purely scientific hypothesis, since it appeals to no agencies 

 save such as are known to be in operation, and involves no 

 assumptions which cannot, sooner or later, be subjected to a 

 crucial test. 



These preliminary considerations show how strong is the 

 legitimate presumption in favour of the theory of derivation. 

 But the case is not to be dismissed upon these summary, 

 though forcible, considerations. To the general reasons here 

 assigned for preferring the theory of derivation to the theory 

 of special creations, a scientific survey of the phenomena 



