Brenchley.—Organic Plant Poisons . //. 
271 
g>a.r*n s 
Fig. 12. Average dry weights of ten 
series of pea plants grown in strong nutrient 
solutions in the presence of differing amounts 
of resorcinol. Sept. 26-Dec. 17, 1914. 
or paralysing influence is not trans¬ 
mitted to the shoot at once, but 
only makes itself felt after some 
time has passed. 
With a rather lower concen¬ 
tration, M/100 x J-, the resorcinol did 
not make itself felt for several days, 
and even then the roots were much 
more affected than the shoots. The 
other phenols, as cresol, orcinol, pyrogallol, &c., the amount of shoot growth 
being most surprising considering the state of the root. Perhaps the effect of 
the resorcinol was in some way to give a stimulus to shoot production, or at 
least to allow it to go on unhindered, so that although no fresh nutrient was 
being absorbed on account of the 
death of the root, yet the shoot was 
able to make use of the stores in 
the seed and develop for some time 
wholly at their expense. This may 
indicate that this particular poison 
is primarily local in its action, and 
that though it kills the root, the lethal 
Tobol 
ShooV 
'Hoo't 
Fig. 13. Average dry weights of ten series 
of barley plants grown in strong nutrients in 
the presence of differing amounts of resor¬ 
cinol. March 16-May 3, 1915. 
roots gradually turned brown, then black ; the laterals were weak and were 
usually formed above the solutions. At a still later date recovery set in, 
and long straight laterals were pushed into the solutions, so that at the end 
of the experiment most of the plants looked fairly healthy, and were not so 
very deficient in dry matter. Lower concentrations had little effect 
on 
