66 o Waring ton .— The Effect of Boric Acid and Borax on 
controls and most of the other sets were fully mature, these plants were 
quite green. Voelcker ( 36 ) has described a similar retardation in his 
experiments on the action of boron on wheat and barley. 
i grm. HoB 0 3 was also injurious, though the poisoning effects were less 
evident than where heavier dressings had been given (Table VIII) ; only 
slight injury in the early stages of growth was apparent in plants grown 
with 0-5 grm. H.,B 0 3 , and lower dressings produced no harmful effect at 
all; in fact 01 grm. seemed slightly beneficial, and a decided increase in the 
Text-fig. 6. Barley grown in pot culture with various quantities of boric acid mixed throughout 
the soil. Feb. 24-July 8, 1921 (average of live pots) : -Weight;-- — • — • per cent. Nitro¬ 
gen ;.Actual N. . 
green weight was obtained, though the rise in the dry weight was only very 
slight (Table VIII and Text-fig. 6). These plants, however, matured 
slightly later than the controls and showed a few isolated cases of leaf 
spotting in the early stages. The untreated plants were in every way 
healthy and well grown, closely resembling the sets treated with the smallest 
quantities of boric acid in appearance and dry weight (Table VIII). 
(b) Boric acid appiied as a top-dressing fifteen days after solving. 
Though barley suffered more injury than broad beans when the boric acid 
was mixed throughout the soil, in the top-dressing experiments the reverse 
occurred. Whereas even 1 grm. per pot completely killed all broad bean 
