Ill REFORMED CONCEPT OF MATTER 53 



tion of new species or elements beyond those already known. 

 The Periodic Table does indeed indicate the vacant places 

 for half a dozen more guests yet to arrive. But the number 

 of elements is definitely and narrowly limited, and we have 

 no reason to look forward to any large increase beyond those 

 already known. In another important respect Radioactivity 

 differs from Organic Descent. Organic Descent professes 

 to show how new and future species arise through variation 

 and selection from those already existing. Radioactivity 

 operates in the opposite direction and indicates how by 

 elimination of certain unit constituents from a complex 

 element there may be established a regress to another 

 simpler known element. In the time-series Organic Descent 

 professes to move forward, while the process of Radio- 

 activity appears to be backward, or to retrace evolutionary 

 steps taken in the past. In still another respect Radio- 

 activity appears to be even more effective than Organic 

 Descent, for it exhibits before our eyes the process of the 

 transmutation of elements, while it is not yet definitely 

 established that any natural species has yet been raised in 

 the laboratory or will ever be raised in any period of time 

 short of geological periods. In a final respect there is a 

 striking similarity between the two factors in that they both 

 appear to proceed by definite substantial increments or 

 decrements in effecting transmutations. Radioactivity expels 

 definite numbers of Helium nuclei as steps in the transmuta- 

 tion of elements. According to De Vries and others the 

 process of advance from old to new species or varieties is by 

 way of definite marked mutations, and not by the slow sum- 

 mation of minute discontinuous variations. And the present- 

 day Geneticists emphasise this similarity still more by iden- 

 tifying all organic variations with differences of chromo- 

 somes or genes in the nuclei of varying or mutating species. 

 The above differences in the operation of the two factors 

 of Radioactivity and Organic Descent arise partly no doubt 

 from inherent differences between matter and life, but also 

 partly from other possible differences in their circumstances 

 of a less fundamental character. Thus life is a mere child on 



