Transformation of Species 241 



investigators to form entirely different opinions. Our ultimate aim 

 is to find a solution of the problem as to the cause of the origin of 

 species. Indeed such attempts are now being made : they are justi- 

 fied by the fact that under cultivation new and permanent strains 

 are produced ; the fundamental importance of this was first grasped 

 by Darwin. New points of view in regard to these lines of inquiry 

 have been adopted by H. de Vries who has succeeded in obtaining 

 from Oenothera Lamarckiana a number of constant "elementary" 

 species. Even if it is demonstrated that he was simply dealing with 

 the complex splitting up of a hybrid \ the facts adduced in no sense 

 lose their very great value. 



"We must look at the problem in its simplest form ; we find it in 

 every case Avhere a new race diflers essentially from the original type 

 in a single character only ; for example, in the colour of the flowers 

 or in the petalody of the stamens (doubling of flowers). In this con- 

 nection we must keep in view the fact that every visible character in 

 a plant is the resultant of the cooperation of specific structure, with 

 its various potentialities, and the influence of the environment. We 

 know, that in a pure species all characters vary, that a blue-flowering 

 Campanula or a red Sempervivum can be converted by experiment 

 into white-flowering forms, that a transformation of stamens into 

 petals may be caused by fungi or by the influence of changed con- 

 ditions of nutrition, or that plants in dry and poor soil become 

 dwarfed. But so far as the experiments justify a conclusion, it would 

 appear that such alterations are not inherited by the offspring. 

 Like all other variations they appear only so long as special con- 

 ditions prevail in the surroundings. 



It has been sho^Mi that the case is quite different as regards the 

 white-flowering, double or dwarf races, because these retain their 

 characters when cultivated under practically identical conditions, 

 and side by side with the blue, single-flowering or tall races. The 

 problem may therefore be stated thus : how can a character, which 

 appears in the one case only under the strictly limited conditions of 

 the experiment, in other cases become apparent under the very much 

 wider conditions of ordinary cultivation '^ If a character appears, in 

 these circumstances, in the case of all individuals, we then speak of 

 constant races. In such simple cases the essential point is not the 

 creation of a new character but rather an alteration of this character 

 in accordance with the environment. In the examples mentioned 

 the modified character in the simple varieties (or a number of 

 characters in elementary species) appears more or less suddenly and 

 is constant in the above sense. The result is what de Vries has 



1 Bateson, Reports to the Evolution Committee of the Royal Society, London, 1902; cf. 

 also Lotsy, Vorlemngen, Vol. i. p. 234. 



D. 16 



