the Broad Bean and certain other Plants. 661 
plants, barley was able to make some growth where a 2 grm. dressing 
had been applied (Table VIII). Difference in seasonal conditions can¬ 
not in any way be responsible for this result, as the corresponding 
experiments with beans and barley were set up on approximately the same 
dates. The duration of the experiments naturally differed owing to the 
longer growth period of barley, but since the injury was always most 
severe in the early stages of growth, this has probably little to do with the 
results. The toxic effects were exactly similar to those previously described 
for barley grown in pot culture. 
A dressing of 4 grm. H 3 B 0 3 per pot completely killed all the plants, 
and though application of 2 grm. or 1 grm. per pot was not sufficient to 
prevent growth, yet the plants were severely injured (Table VIII), no ears 
being formed in the former sets, and the ripening off being noticeably 
retarded in both cases. Where 05 grm. H 3 B 0 3 was applied, this lateness 
in maturing was still seen and the leaves were badly spotted ; however, 
a rise occurred in the green weight, though the dry weight was decidedly 
depressed (Table VIII). The lower dressings caused no injury, leaf 
spotting being evident in isolated cases only; in fact the effect was slightly 
beneficial, a distinct rise in the dry weight being obtained with the o-i grm. 
application (Table VIII), and both this set and the plants treated with 
o-o2 grm. appeared to the eye rather better than the controls, though similar 
in degree of maturity. 
/3. Comparison between the Effect of Boric Acid and Borax in the Soil. 
The dressings of boric acid and borax were made immediately after 
sowing in this case, i-o boric acid being equivalent to 1*54 borax. 
1 grm. boric acid and the corresponding borax application caused a 
marked retardation in germination, and the shoots were of the characteristic 
yellow-pink colour ; boron was again detected in the liquid exuded from 
these chlorotic seedlings. 
Contrary to what occurred in the case of the broad bean, borax seemed 
more injurious than boric acid to barley, a result similar to that which 
Voelcker ( 36 ) obtained in 1915. For example, fewer plants died in the set 
grown with 1 grm. of H 3 B 0 3 , and the survivors made an earlier recovery 
and remained considerably better for some time than the corresponding 
borax-treated plants. However, at the close of the experiment there was 
little to choose between them, ears being formed in all cases and a similar 
retardation in maturing being apparent; both the green and dry weights also 
were very similar (Table IX). This may possibly be explained on the 
ground that the more soluble borax would permeate the soil more quickly, 
and therefore affect the plant more severely at first, but, since the quantity 
of boron in both cases was the same, the ultimate effect of the two com¬ 
pounds would be similar. The dark blue-green colour of these sets was 
