in.] ORGANIC STABILITY. 33 



whose descendants had reverted ; they might be looked 

 upon as tentative and faltering steps taken along parallel 

 courses of evolution, and afterwards retraced. Affiliation 

 from each generation to the next requires to be proved 

 before any apparent line of descent can be accepted 

 as the true one. The history of inventions fully illus- 

 trates this view. It is a most common experience that 

 what an inventor knew to be original, and believed to 

 be new, had been invented independently by others 

 many times before, but had never become established. 

 Even when it has new features, the inventor usually 

 finds, on consulting lists of patents, that other inventions 

 closely border on his own. Yet we know that inventors 

 often proceed by strides, their ideas originating in some 

 sudden happy thought suggested by a chance occurrence, 

 though their crude ideas may have to be laboriously 

 worked out afterwards. If, however, all the varieties of 

 any machine that had ever been invented, were collected 

 and arranged in a Museum in the apparent order of 

 their Evolution, each would differ so little from its 

 neighbour as to suggest the fallacious inference that the 

 successive inventors of that machine had progressed by 

 means of a very large number of hardly discernible 

 steps. 



The object of this and of the preceding chapter has 

 been first to dwell on the fact of inheritance being 

 " particulate," secondly to show how this fact is com- 

 patible with the existence of various types, some of 

 which are subordinate to others, and thirdly to argue 



D 



