NILSSON'S DISCOVERY 95 



harvest, especially when it is difficult to keep the cultures 

 clean from vicinistic impurities. A race which is really 

 self-dependent may in this way seem to be permanently 

 related to the continuous selection of its pedigree. Such 

 races have been produced at various times by Heine in Ger- 

 many for rye and wheat, by Drechsler in Gottingen for rye, 

 by Mokry in Hungary for wheat, and in many other instances. 

 It is especially in Germany that this method of slow im- 

 provement is adhered to and has given admirable results. 

 One of the best known instances, and for which the histori- 

 cal records are the most complete, is the famous rye of 

 Schlanstedt, produced by Rimpau, which is now largely 

 cultivated all over the central part of Germany and the 

 northern districts of France. In the year 1876 I had the 

 privilege of visiting Mr. Rimpau on his farm at Schlanstedt 

 and of studying his cultures. The elite of his new rye was 

 standing on a small parcel out in the fields, but surrounded 

 by cultures of vegetables and other plants not belonging to 

 the cereals. These minor cultures occupied a large square, 

 which in its turn was surrounded by a complete range of 

 shrubs. Thus, the rye, standing in midst of the square, was 

 sufficiently removed from the neighboring fields to insure it 

 against possible contamination by pollen of other varieties. 

 On the other hand, it was given the same soil and exposure 

 and almost the same cultural treatment as the average cultures. 

 This race had been started by Rimpau nine years before, 

 in the year 1867. At the time of the harvest of that year he 

 inspected, as he told me, a large number of his rye fields 

 and selected all the ears which seemed to him to noticeably 

 surpass the others. He brought home a handful of them, 

 repeated the trial, and mixed their seeds. This mixed con- 

 dition in the beginning of his race has now become the 

 weak point, where the whole principle of his method is 

 open to criticism, as we shall soon see. 



