4 Livingston : Chemical stimulation of a green alga 



This investigation was begun and about half finished in the 

 laboratories of the New York Botanical Garden, where it was my 

 good fortune to hold a research scholarship during the autumn of 

 1903. Through the kindness of the Director in Chief and of the 

 Director of the Laboratories, the facilities for the work were prac- 

 tically unlimited. The experiments were completed at the Hull 

 Botanical Laboratory of the University of Chicago during the 

 winter and spring just passed. 



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Figure i . Normal filaments, from weak nutrient solution. 

 FIGURE 2. Normal palmella, from strong nutrient solution. 



Methods 



A modification of the well-known Knop's nutrient solution 

 was used as a basis for the culture media and for the controls. 

 The differences between this and the true Knop's solution are 

 such as to make the former more easy of preparation when the 

 chemistry of the mixture is to be considered. The formula, and 

 certain physical properties of this standard culture medium are 

 shown in the following table. The concentration data for the salts 



