THE CAUSATION OF DISEASE. 289 



the complexity of the E. Now, remembering our criterion of 

 naturalness, when are we to say that the artificial E begins 

 and the natural E ends ? The E of the ape-like man, as we 

 look back and try to realize it, appears very artificial as com- 

 pared with that of his more primitive ancestors ; that of the 

 savage, again, highly artificial as compared with the E 

 of the ape-like man, and our own stands out as yet more 

 highly artificial compared with that of the savage. Yet to all 

 there is, or has been, adaptation ; and since the extent of the 

 adaptation determines the degree of the " naturalness," the 

 limits of what can be termed artificial E become more and 

 more restricted. The same line of argument might be pursued 

 in respect of any member Or section of a civilized community 

 having increasingly complex E's ; and, viewing the matter 

 thus, it becomes yet more evident that there is no sharp dis- 

 tinction between a natural and an artificial E. 



