3°o 



BOTANICAL GAZETTE 



Experiments and results 



In order to determine the relative toxicity of these various 

 solutions to Tradcscantia, cuttings of the plant were placed in 

 various dilutions of each solution with redistilled water. In this 

 way the percentage of the solution (that is, the number of cc. 

 diluted to ioo with redistilled water) that would allow the forma- 

 tion of roots but inhibit the production of root hairs was determined. 



All of the solutions except 5A were acid to both litmus and 

 phenolphthalein. Their acidity was determined by titratuig with 

 N/10 NaOH, using phenolphthalein as an indicator. 



Table I gives the toxic limits of these solutions to Tradcscantia 



(as previously defined) and their acidity, together with the relative 



rank of each solution as to toxicity and acidity and the ratios of 



these. 



TABLE I 



All of the solutions mentioned in table I, except $B, were 

 neutralized to phenolphthalein with N/10 sodium hydrate, and 

 the effect of both the acid and the neutral solution was tried on 

 Tradcscantia cuttings. Table II shows the results of the dilutions 

 named on Tradcscantia cuttings. 



TABLE II 



