DAVID I. MACHT AND MARGUERITE B. LIVINGSTON 583 



tive toxicity of the two for animals. Methyl alcohol was found to be 

 not very toxic for either animal tissues or lupine roots. The most 

 remarkable results obtained, however, were those with sodium ben- 

 zoate. This salt is very slightly toxic indeed for animal tissues, so 

 that it is employed as a food preservative, yet it was found to be the 

 most toxic of all the compounds studied for lupine roots. It required 

 a concentration of only 0.007 per cent to kill the plants. Methyl 

 benzoate was also very toxic, being second only to sodium benzoate 

 in that respect. 



The reason for the remarkable difference just pointed out, in the 

 toxicity of cocaine for animal and for plant tissues, is as yet unknown. 

 The effects of the drugs studied are certainly not attributable to a 

 simple change in the hydrogen ion concentration of the culture media, 

 for experiments made by the authors showed that the Shive solution 

 may be made more or less acid or alkaline without appreciably affect- 

 ing the growth of the lupine roots. The value of the pH of the normal 

 Shive solution here used was 6.4. More acid and less acid solutions 

 were prepared by varying the quantity of potassium phosphate used, 

 and it was found that the hydrogen ion concentrations varied from 

 4.4 to 7.2. Within these Umits the growth of lupine roots was very 

 little affected. 



SUMMARY. 



1. The effects of cocaine and its decomposition products were 

 studied on the growth of the young roots of Lupinus albus. 



2. The results obtained were compared with similar experiments on 

 animal tissues. 



3. It was found that, while cocaine is the most toxic of these com- 

 pounds studied for animal tissues, it was of comparatively low toxicity 

 in respect to its effect on the growth of roots. On the other hand, 

 sodium benzoate, being practically non-toxic for animals, was the 

 most toxic of the compounds studied for the plant roots. 



BIBLIOGRAPHY. 



1. Brenchley, W. E., Inorganic plant poisons and stimulants, Cambridge, 1914. 



110. 



2. Bokorny,T., Biochem.Z., 1913,1, 1. 



