158 DARWINISM AND THE PROBLEMS OF LIFE 



as relics of the second and fourth fingers ; we can 

 recognise them as such the more confidently as we 

 can trace in geology every stage in the gradual 

 degeneration of these fingers in the horse's ancestors. 

 These degenerate structures are known as rudimentary 

 organs ; they lend great support to the theory of 

 evolution. If the animals were created separately, 

 why were they endowed with these quite useless 

 appendages? We can only understand them when 

 we admit that they were fully developed and useful, 

 in the ancestors of the particular animal, and that in 

 their descendants, which had no further use for them, 

 owing to change of habits, they could not entirely 

 disappear, because the animals had inherited them 

 and transmitted them in their turn. 



We find rudimentary organs of this kind in almost 

 every species of animals. Man himself has a large 

 number of them — nearly a hundred. Amongst others 

 there are the last two ribs, the wisdom-teeth, a process 

 of the shoulder-blade — the caracoideum, a vesicle in the 

 brain that we call the pineal body, and the worm- 

 shaped appendage of the coecum. The latter is not 

 only superfluous, but even dangerous, on account of 

 the inflammation (appendicitis) that may be set up in 

 it by the penetration of foreign bodies. There were 

 vegetarian mammals amongst our ancestors. And in 

 plant-eaters the ccecum is often indispensable, and is 

 often longer than the whole body of the animal. 



In the same way the caracoid process of our shoulder- 

 blade is an important bone in reptiles, amphibians, and 

 birds ; and in the pineal body we have the last relic of a 



