ASPECTS OF KINETIC EVOLUTION 325 



"Thence we must conclude that new species are produced 

 sideways by other forms, and that this change only affects the 

 product, and not the producer. The same original form can in 

 this way give birth to numerous others, and this single fact at 

 once gives an explanation of all those cases in which species 

 comprise numbers of subspecies, or genera large series of 

 nearly allied forms." 1 



These inferences were made, of course, without reference to 

 the kinetic conception of evolutionary motion as a specific struc- 

 ture or network of descent. Nor is the possibility considered 

 that a small group of individuals isolated and inbred in a foreign 

 land might behave in an abnormal manner, or at least in a 

 manner that would afford small indication of the normal mode 

 of evolutionary motion. Other parallel cases observed in coffee, 

 cotton, capsicum, tea and other plants, indicate that mutative 

 variations like those of the evening primrose are the regular re- 

 sults of the treatment to which the plants have been subjected 

 in domestication. Instead of illustrating the method by which 

 evolutionary advance is accomplished, mutations appear to 

 represent a stage in the degeneration of organisms which have 

 been removed from the vital fabric of specific descent ; they do 

 not show how the evolutionary network is woven, but how the 

 strands can be unraveled. Conditions of uniformity like those 

 of inbred domesticated varieties are to be found in nature only 

 exceptionally, in the relatively few degenerating types which 

 have become regularly addicted to self-fertilization or to vege- 

 tative propagation. Nor do we find under normal evolutionary 

 conditions of symbasic interbreeding and individual diversity 

 these violent mutative departures from the parental types. 

 There is a vastly greater range and flexibility of characters 

 and character-combinations. Nevertheless, it is very doubtful 

 whether a species as a whole would make an appreciable evo- 

 lutionary advance in eighteen years. In any event, the fact 

 could hardly be determined from a few specimens in a foreign 

 garden. 



All kinds of variations can be described as having been pro- 



1 De Vries, H., 1905. The Evidence of Evolution. Smithsonian Report for 

 1904, p. 396. 



