722 



SCIENCE. 



[N. S. Vol. XV. No. 384. 



opened for thoughts, for observation, or 

 comparison and the drawing of conclusions. 

 The result was a hard-fought war, openly 

 carried on against Darwin, and ending in 

 his complete victory. But before we were 

 able to declare ourselves advocates of the 

 new doctrine, the bonds which held us were 

 to be severed, and we had to break loose 

 from the old prejudices. 



Of the present generation none have 

 Imown this internal struggle. They have 

 been brought up in the new doctrine. The 

 common descent of species and genera is 

 for them a dogma, as much as the creation 

 of species was for their fathers. With 

 different eyes they watch the progress of 

 science in this new teiTitory. They neither 

 feel the pride of the victor, nor have 

 they the personal example of Darwin's un- 

 tiring labor. It is much to be regretted that 

 everywhere, in the manner of both working 

 and thinking, we find evidence of this. 

 Deductive treatment has taken the place of 

 observation and investigation. An im- 

 mense superstmcture of speculative science 

 has risen on the foundation of Darwin's 

 selection theory. The possible influence 

 of selection in past times has been discussed 

 for numerous cases, but its actual influence 

 at the present time was left uninvestigated. 

 Thought, instead of Nature, became the 

 source of theory, and the latter conse- 

 quently became farther and farther re- 

 moved from the truth. 



At last the tide is turning. Conn, in a 

 recent book on evolution, exclaims : ' Let us 

 leave our books and return to Nature, ' add- 

 ing, 'leave speculation and turn to obser- 

 vation.' The necessity of this is making 

 itself felt everywhere. The time of con- 

 templation is past. We no longer ask how 

 things m.ight he; how things are is the ques- 

 tion of the hour. 



De Varigny, the well-known French 

 translator of Wallace's book on 'Darwin- 

 ism,' formulates as the first requisite, viz., 



that we should see species originate. It 

 is no longer sufficient to be convinced that 

 it is so, we must know it from experience. 

 During the last decade a few investigators 

 have sought the paths which lead to this 

 goal. It is but recently that the results 

 they obtained have been published. And 

 though the paths followed are very diver- 

 gent, and the results differ greatly, yet for 

 all the initial point was Darwin's book; 

 none were influenced by subsequent specu- 

 lations. Darmn's theory of adaptation 

 led to the investigations on the origin of 

 species in the Alps by Kerner and von 

 AVettstein; Darwin's selection theory to 

 the statistical investigations of variability 

 by Galton and Weldon, and to the mathe- 

 matical studies of Karl Pearson. And 

 likewse finding its origin in Darwin's 

 great work, stands the study of discontin- 

 uous variability, the study of the single 

 variations or mutations,* and the question 

 whether in these must be sought the origin 

 of species. 



Only a single case has been discovered in 

 which it is possible to actually see species 

 originate ; and this not accidentally, but ex- 

 perimentally, so that one can watch and 

 carefully foUoAV the manner of their origin. 



Three kinds of evening primroses occur 

 in Holland, all three introduced from 

 America about a century ago, but since 

 escaped from cultivation. The youngest of 

 the three, or rather the one most recently 

 introduced, and at the same time the most 

 rare, is the large-flowered evening primrose, 

 described at the beginning of the nine- 

 teenth century by Lamarck, and named 

 after him Oenothera Lamar c.kiana. It is a 

 beautiful, freely branching plant, often at- 

 taining a height of five feet or more. The 



* Sudden variability, comprising the deviations 

 from the rules of heredity in the wider sense, as 

 opposed to fluctuating variability, e. g., the degree 

 of variability peculiar to each character of a 

 species. Hugo de Vries, ' Die Mutationstheorie.' 

 Leipzig, Veit & Co. 19.01. 



