THE VITAL FABRIC OF DESCENT 3I9 



means by which the constructive evolution of nature has gone 

 forward. 



There can be no certainty that any particular species may 

 not, at some remote period and place, be crowded into a narrow 

 corner of the environment, and made to yield degenerative 

 mutations, but this possibility should not cause us to forget that 

 the broad fabrics of continuous, diverse, and gradually chang- 

 ing descent are being woven in the living looms of all the wide- 

 spread species in nature. To say with Professor Haeckel and 

 others that the abnormal is the important for evolution, is not 

 merely to frame a paradox, it is to confess what in theological 

 language would be termed a most pernicious heresy. For do 

 not isolation and inbreeding represent the very principle and 

 essence of biological evil, the ever-present danger of deteriora- 

 tion, which nature is taking such infinite pains to escape, by all 

 the devices of sex and symbasis? All new characters must, 

 indeed, be classed as abnormal if we think of species as nor- 

 mally constant and stationary, but to base evolution on the 

 degenerate abnormalities of inbreeding darkens counsel indeed. 



The acceptance of the laws of planetary motion was impeded 

 by mediaeval theology, but thought is now clouded by the 

 opposite tendency, an equally unscientific fear to admit the 

 reality of phenomena not immediately explainable in current 

 terms of physics and chemistry.^ The facts of vital motion are 

 obscured by mechanical dogmas, vastly complicated, and yet 

 wholly incompetent. In terms of physics and chemistry, we 

 do not know zvhy cousins may not marry, why inbreeding is 

 destructive, or why symbasis is necessary to maintain organic 

 strength and evolutionary progress ; but we may be certain 

 that evolutionary doctrines which disregard such primary facts 

 of descent are fatally defective. 



Current theories require that new characters be saved by 

 segregation, but organisms are not like chemical compounds, to 

 be preserved by keeping them from contact with others. Pro- 

 toplasmic compounds are noted, it is true, for their extreme 

 lability or tendency to decompose as soon as life is extinct, but 

 this fact, instead of proving that vital processes are due to the 



1 Evolution and Physics, Science, N. S., 20 : 87, July 15, 1904. 



