DAVID I. MACHT AND MARGUERITE B. LIVINGSTON 579 



per cent, to kill the plant, while 1 molar, or 3.2 per cent, gave a growth 

 increment of 27 per cent, or as large as occurred in the controls. 

 Concentrations of 0.1 molar, or 0.32 per cent, gave results suggestive 

 of a stimulation of root elongation. 



Efect of Sodium Benzoate and Methyl Benzoate. — The results ob- 

 tained with these compounds were most interesting, as shown in 

 Tables V and VI, It was found that these esters were both very toxic 

 for lupine roots. Solutions of sodium benzoate as dilute as 0.305 

 molar, or 0.007 per cent, completely inhibit growth, while methyl 

 benzoate produced complete inhibition in concentrations of 0.0001 

 molar, or 0.014 per cent. 



Efect of Some Mixtures. — Inasmuch as combinations of drugs in 

 animal experiments often give synergistic or antagonistic results, 

 experiments were made with various mixtures of some of the com- 

 pounds above considered. Four sets of mixtures were prepared and 

 labeled respectively A, B, C, and D, Mixture A consisted of sodium 

 benzoate, methyl alcohol, and ecgonine hydrochloride, the quantity 

 of each used being one-third of the individual lethal dose. Mixture 

 B consisted of sodium benzoate, methyl alcohol, and ecgonine hy- 

 drochloride, the quantity of each used being one-third of the individual 

 lethal dose. Mixture C contained one-half of the lethal doses of 

 ecgonine hydrochloride and methyl benzoate, respectively. Mixture 

 D contained one-half of the lethal doses of benzoyl ecgonine and 

 methyl alcohol, respectively. These mixtures were employed in 

 some experiments in their original concentrations, and in other ex- 

 periments dilutions of these mixtures were tried. It was found, as 

 might have been expected, that Mixture A produced death of the 

 plants. It was furthennore found that, when Mixture A was diluted 

 to one-half the original concentration, it still produced death; in other 

 words, it gave a synergistic effect. Mixture B was also found to be 

 more toxic than was to be expected from a simple summation of its 

 individual components. On the other hand, Mixtures C and D were 

 found to be slightly less toxic than the arithmetical sum of their 

 component effects; in other words, they suggest a slightly antagonistic 

 action of the components against each other. 



