Brenchley. 
Organic Plant Poisons. 
II. 
275 
TcItoA. 
shows the mean dry weight of those plants which made a good recovery, 
and also of those which hung back to the last. Although the roots were 
injured directly they entered the solutions, the shoots were not affected at 
first and were as good as those <rr«*w, s 
of the control plants. After 
a time the shoots began to feel 
the defection of the roots, and 
as insufficient nutriment was 
supplied to them their growth 
suffered, though they re¬ 
mained green and healthy all 
along. The improvement in 
root growth was strongly 
reflected by that in the shoots, 
and the plants made rapid Shoob 
headway when once root re¬ 
covery had set in. Some mould 
appeared on the roots at an 
early stage, but did not seem 
to interfere with recovery. 
With the next lower con¬ 
centration, M/ico x 1/5 2 , the 
toxic action was much less 
marked. For a little time the 
root laterals were rather short 
and somewhat discoloured, 
and before very long some ~Roo\ 
degree of distortion appeared, 
but later on growth became 
more normal and the plants 
approximated in appearance 
to the controls. 
All the lower strengths 
of orcinol had little or no 
effect upon growth, as the 
plants compared very favour¬ 
ably with the controls. 
Barley . 
Fig. 18. Average dry weights of ten 
A comparison of the serie . s of ba . r]e y . plants grown in strong 
r , . nutrient solutions in the piesence of differing 
curves lor barley and peas amounts of orcinol. Mar. 27-May 17,1915. 
shows that bailey is more sensitive to the action of orcinol, as so often 
happens with these poisons. The highest concentration, M/100, probably 
T 3 
