The theory of seed steriHzation was further developed by Wimmer, one 

 of Hellriegel's collaborators. Of the different substances used in sterilizing, 

 carbolic acid was proved to be the most advantageous and, in fact, when 

 used in the one per cent, solution of "Acidum carbolicum crudum lOO per 

 cent. Pharm. Germ. II." To one part by weight of seed should be reckoned 

 about 6 to 8 parts by weight of liquid. A warm water solution was proved 

 favorable as well as a cold water solution\ 



While Wimmer left the question undecided as to the influence of the 

 weather and the soil constitution Holdefleiss held to the theory that this 

 and not parasitism caused rootblight. In soils favorable to the disease, he 

 usually found an abundant amount of ferrous oxid, but comparatively little 

 calcium. In this the tendency to choking with mud and incrustation of the 

 soil are unmistakable and the discovery that rootblight was cured by abun- 

 dant hoeing was in accordance with this. On this account Holdefleiss 

 recommends, in addition to a continued, open condition of beet soils, a rich 

 addition of burned (quick) lime (12 to 15 centner German per acre)- which 

 is given with the best results to the first grown crops and not directly to the 

 beet. Loges^ had good results from the addition of 7 cent, of quick-lime per 

 acre. As a further contributory factor, Ilollrung emphasizes a lower temper- 

 ature and the fact that rootblight never extends above the surface of the soil 

 to the aerial parts of the axis which are exposed to air currents. He asserts 

 definitely that rootblight is brought about by physical and chemical causes 

 making themselves felt in cold soil, impermeable to air currents. The theory 

 that the soils, in which black leg of the beet occurs, are easily choked with 

 mud and become hard is substantiated by Marek and Krawczynski. Ac- 

 cording to Stiffs statement (loc. cit. 10 to 20) in such a soil 77.25 per cent, 

 fine sand was found. 



Opposed to these theories, shared by many other investigators, the par- 

 asitic theory was still maintained and found its most active defender in 

 Frank. Frank, with Kriiger, from 1892 on, made various experiments and 

 determined that, besides the Pythium de Baryanum found by Lohde, and oc- 

 curring in many diseases of seedling plants from very different genera, be- 

 sides the Rhicoctonia violacea mentioned by Eidam, there was a specific 

 beet fungus, Phoma Betae Frank, "which not onlj^ causes heart and dry rot 

 of the mature beet, but also the rootblight of the young beet roots."'' Re- 

 peated discoveries in field experiments, however, soon showed even this 

 investigator that weather and soil conditions exert a decisive influence. "It 

 is still undecided whether the seedUng thereby becomes more susceptible to 

 the fungus attack or whether this is not sufficiently explained by the fact 

 that cold weather delays the growth and the plant remains unusually long 



1 Hollrung, in Zeitschr. f. Rubenzuckerindustrie i. D. R. Vol. 46. Part 482. 



2 J. Centner in German weights equals 50 kg-, or approximately 112 English 

 pounds. 



3 Bericht. d. Landw. Versuchsstation Posen. 1891. 



4 Frank, A. B. Kampfbuch gegen die Schadlinge unserer Feldfruchte. Berlin, 

 Paul Parey, 1897, p. 117. 



