4 EVOLUTION IN THE PAST 



Inter-struggle in localities of congestion, temperature, 

 chemical action, and other forces of environment undoubtedly 

 prompted the putting forth of variations, but they cannot 

 have produced the power to vary. 



The course of evolution is hard to reaUse. The difficulty, 

 however, is lessened by bearing some facts in mind. The cell 

 is the unit of life ; every organism of whatever degree begins 

 its existence as a single minute cell ; and all hfe-forms 

 above the lowest are cells in combination. All organisms, 

 therefore — from the highest to the lowest— are in a sense 

 intimately related. 



In the vast majority of cases the initial variations that 

 led to new forms were probably extremely shght. Organisms 

 remained much the same as their parents. Important changes, 

 however, came to be chronicled when small variations of a 

 useful kind had been accumulated and intensified through a 

 series of generations. That, at least, is the view that Charles 

 Darwin propounded ; and it has been accepted by most 

 evolutionists. 



From researches — chiefly botanical — pursued in recent 

 years by Hugo de Vries and W. Bateson, it has been claimed 

 that variations not infrequently are of a pronounced character. 

 It is also claimed — on somewhat fragile evidence — that that 

 is the usual method whereby new species appear. For such 

 substantial changes suddenly effected the name of " muta- 

 tions," also of " explosions " (Deperet), has been given. 

 There is certainly evidence that developments of this character 

 take place; and the fact was admitted by Charles Darwin, 

 and other evolutionists of the time. It was, however — and 

 still is — urged that such phenomena very seldom occur ; and 

 that they are in fact sports and monstrosities that cannot be 

 perpetuated in wild Nature. Nor has this view been proved 

 to be incorrect, although Mendel's discoveries show that in 

 domesticated Nature, mutations, repressed in one generation, 

 reappear in another. 



Although not quite in line with a portion of Darwinism, 

 the Mutation Theory, of course, does not affect the general 

 doctrine of Evolution. Should it ever be established — and it 



