﻿1903] CHEMICAL STIMULATION ^^ 



action of dilute poisons, well established in those organisms 

 physiologically nearest them, the bacteria, led Hueppe'^ to the 

 formulation of this ** biologischen Grundgesetz :'' 



Jeder Korper, der in bestimmler Concentration Protoplasma todtet und 

 vernichtet, in geringeren Mengen die Entwickelungsfahigkeit aufhebt, aber 

 in noch geringeren Mengen, jenseits eines Indifferenzpunktes, umgekehrt 

 als Reiz wirkt und die Lebenseigenschaften erhoht. 



Ono (/. ^,) detected an acceleration of the growth of algae 

 by all the same substances to which his fungi responded, except 

 Hg ; but found the optimum concentration much lower, corres- 

 ponding to the greater susceptibility of the alga to injury by 

 these poisons. 



Our information on the chemical stimulation of the growth 

 of phanerogams is altogether fragmentary. The most familiar 

 example of this is the exceptionally luxuriant growth of violets 

 and some other plants in the neighborhood of zinc works. 

 Rumm"'^ finds that in grape vines sprayed with copper various 

 leaf tissues become better developed, and the fruit ripens earlier. 

 Berlese and Sostegni'^ substantiate this, but seem to believe 

 that the most important immediate effect of the copper is the 

 increase of the cyanophyll, other effects being results of this. 

 Frank and Kriiger^^ show that potatoes sprinkled with copper 

 solutions excel in leaf area, length of life, and amount of crop. 

 Townsend finds that the growth of Avena seedlings is accelerated 

 at least temporarily by not too much ether in the atmosphere ;'7 

 that the germination of various seeds and spores maybe hastened 



'3HUEPPE, F., Naturwissenscbaftliche Einfiihrung in die Bakteriologie. Wies- 

 baden. 1896. Hueppe gives Arndt and Schultz joint credit with himself for this 

 generalization. 



'-^ RUMM, C, Ueber die Wirkung der Kupferpraparate bei Bekampfung der 

 sogenannten Blattkrankheit der Weinrebe. Ker. Deutsch. Bot. GeseUs. ii:79'93' 

 1893. 



'S Berlese et Sostegni, Recherches sur Faction des sels de cuivre sur'> veg^a- 

 tion de la vigne et sur le sol. Rev. internat. de Vitic. et Oenologie. 1895. [Bot, 

 Jahresber. 23': 292-294. 1895.] 



Frank, B., und Kruger, F., Ueber den Reiz welchen die Behandlung mit Kupfer 

 auf die Kartoffel hervorruft. Ben Deutsch. Bot. Gesells. 12:8. 1894. 



'7To\VNSEND,C. O., The correlation of growth under the influence of injuries. 

 Ann. Botany u : 509-532. 1S97. 



