THE LATEST STAGE 255 



While the relationships and similarities between 

 different species point to a common origin, and enable 

 us to assert a near connection between certain types, 

 such as man and ape, the facts seem to warrant little 

 else. We cannot tell what really happened in former 

 ages, when, perhaps, the stream of protoplasm was 

 more plastic and more variable than it is to-day. 

 The elaborate theories of descent which have succes- 

 sively traced the origin of the vertebrates to amphioxus, 

 worms, spiders and crayfishes, have been compared 

 in scientific value by Emil du Bois-Reymond with 

 the pedigrees of the heroes of Homer. 



If we accept the conception of descent, the theory 

 of evolution and no one proposes to jettison it the 

 evidence of purposefulness in living beings suggests 

 that some unknown principle of organization must 

 have been at work from the very beginning. Here 

 again we are brought back to neo- vitalism. 



Whether these vitalistic tendencies will persist, 

 and crystallize into a consensus of opinion, it is im- 

 possible to say. The analogy of the past points to 

 the probability that here too we are but watching a 

 passing phase in the rhythmic wave of human thought. 

 Perhaps some new " explanation " of vital phenomena 

 may be offered in the years to come, and once more 

 give rise to a complete mechanical conception of life. 

 Once more mechanism may fail when subjected to a 

 closer scrutiny, and a still newer vitalism come to its 

 own. Let us at least hope that each alternation may 

 mark a step in knowledge, and lead to the more 

 exact formulation of fundamental problems which 

 as yet we can but dimly discern. The historian 

 of thought tends to be sceptical about ultimate 



