1896] TOXIC ACTION OF DISSOLVED SALTS IIg 
Benzoic and hippuric acids (tables 64 and 65) are both rela- 
tively weakly dissociated, the former 21.61 per cent. and the 
latter 37.51 per cent. at the dilution 1024, according to Ost- 
wald. Both of these acids kill the lupines until the concentra- 
tion 4755 gm. mol. per liter is reached. It is not probable that 
these weak acids are completely dissociated even at this great 
dilution. The result shows that here the toxic effect is due ina 
high degree to the undissociated molecules and the anions pres- 
ent. Whether the undissociated acid is more poisonous than 
the anions can be determined by testing the action of the 
sodium salts. 
66. CINNAMIC ACID. 
(Begun January 23, 9 P.M.; closed January 24, 12 M.) 
Concentration 
gm. mol, per liter Length Remarks 
woo 5° turgor lost, dead 
he aa “ ‘“ “e “ 
16 v .. ee é “ “ 
eee 16 5 “ec “ “cc “ 
saya 18.0 iad “ “ “ee 
neta 17. “ “ ‘“ ‘“ 
stor ae “ ae “ee oe 
ee 20 5 “s “c “ “6 
rat00 29:5" turgid, apparently normal 
eta shes ty £3 “ “ “ “ 
Cinnamic acid (table 65) is only dissociated to the extent 
i 17.34 per cent. at 1024, and yet in a solution of it the 
lupines will not survive until the acid is diluted so that it con- 
tains only ryia5 gm. mol. per liter. At this dilution we know 
that hy drogen ions are no longer harmful to the plants, hence 
om Strong toxic action of this acid is due to the anions and the 
undissociated molecules present in the solution. 
Th Another interesting group is that of the oxy-benzoic acids. 
5 results obtained from the three monoxy-benzoic acids are 
he hoa 7 to 69. It will be seen that salicylic acid has 
8reatest poisonous action, the seedling surviving ina solution 
