True auJ Iluukel, The Poisouous Effect Exerted etc. 391 



The PoJsonous Effect Exerted on Living Plants by 



Phenols. 



Bv 



Rodney H. True, Ph. D., and Carl G. Hunkel, B. S.^) 



(Conclud.) 



If the introduction of tliis raclicle into tlic phenol molecule 

 increases its toxic effect to so considerable an oxtent, the ques- 

 lion arises concerniiii^- its effect when introduccd into othcr Com- 

 pounds. 



By replacing one 11 of the henzenc ring with an NOj gi'oup, 

 WC have nitrobenzene, a Compound differing from the nitrophenols 



just studied by having nonc of its H hydrogens rephiced by the 



+ 

 OH group. In nitrobcnzene, consequently, wc can liave no 11 ions. 

 Since the introduction ot OH groups does not nu\terially affeet 

 the toxicity of a Compound dissociating but slightly, as resor- 

 cino], we may comparc the toxic effect of nitrobcnzene with that 

 of the nitrophenols Avhich do not dissociate ; i. e., when no H 

 ions are present. This is realized when Na OK is added to the 

 nitrophenols. 



Nitrobenzene, CöIIsNOl'. 



Table XXXVI. 



Begun Mar. 2, 8 : 25 P. M. 

 Gram-mol. per liter. Lonpith Mar. 3. 



3 :"4rj P. M. 

 1/1600 



1/3200 



1/6400 



A comparison ot Tables XXXIII and XXXVI shows that 

 the toxic valuc of para-nitrophenol + 1 Na OH is found to be some- 

 what greater than that of nitrobenzene, the lattcr, howevcr, bcing 

 still strongly poisonous. Its toxic action is about cqual to that 

 of ortho-nitrophenol -\- 1 Na OH (Table XXX). 



Returning to the phenol Compounds, we may ask, in view 

 of the destructive results secn to foUow the introduction of one 

 NO2 group into the phenol molecule, what may be the effect of 

 the presencc of a larger number of these groups. Unfortunately, 

 dinitrophenol, Cg H:j (OH) (NO-Oa, was not available, picric acid, 

 trinitrophenolj only being at band. 



