Brenchley.—Organic Plant Poisons. II. 
265 
Cresol, 
Very little seems to be known about the occurrence of the cresols in 
the Vegetable Kingdom, nor of their effect on plant life. Wehmer 1 states 
that the flowers of Acacia Farnesiana yield /-cresol, and that certain 
members of the family Burseraceae contain M-cresol. The three cresols are 
gvahr, s 
I'Z 
bO 
*9 
•6 
•A 
Z 
I = H X 
16 o 5 
Fig. 6. Average dry weights of ten series 
of pea plants grown in strong nutrients in 
the presence of differing amounts of 0-cresol. 
Oct. 5-Dec. 21, 1914. 
"ToFeJl 
ShooF 
Hoot* 
Fig. 7* Average dry weights of ten series 
of pea plants grown in strong nutrient solu¬ 
tions in the presence of differing amounts of 
w-cresol. Oct. 6-Dec. 21, 1914. 
N.B. 5 4 . Upper curve = mean of plants 
which made good recovery. Lower curve = 
mean of plants which made poor recovery. 
all toxic, but in varying degree. 
Tokens 2 indicates that in animal 
investigations ^-cresol is about as 
toxic as phenol, /-cresol being 
more poisonous, ^-cresol rather 
less so. No reference to this re¬ 
lative toxicity with regard to 
plants has so far come to light. 
Consequently barley and peas 
have been tested with all three 
forms in the usual way. 
Peas (Figs. 6, 7, 8). 
All the plants were started 
at the same time, and the growth 
of the series treated with the 
three cresols was remarkably 
bO 
/ ! 
/ i 
/ / 
/ / 
/ ' 
I * 
f 9 
/ 
/ 
_— 
/ 
"Tob<xl 
ShooV- 
*KooV 
s* 5“ S* 5' s I 
1 - £■ * f t 
IOO c) 
Fig. 8. Average dry weights of ten 
series of pea plants grown in strong nutrients 
in the presence of differing amounts of p - 
cresol. Oct. 5-Dec. 21, 1914. 
1 Wehmer: Die Pflanzenstoffe. 1911. 
2 Tollens, quoted by Robert, R. : Lehrbuch der Intoxikationen. 
Auflage. 1902-6* 
