The Effect of Boric Acid and Borax on the Broad 
Bean and certain other Plants . 1 
BY 
KATHERINE WARINGTON, M.Sc. 
(Rothamsted Experimental Station.') 
With Plate XIII and six Figures in the Text. 
Contents. 
TAGE 
I. Introduction. 630 
II. Experimental Work.631 
1. Water Cultures .............. 6^5r 
A. Broad Beans . ..... ....... 632 
a. 1 he effect of different concentrations of boric acid in the nutrient solution . . 632 
(a) Development of the root.632 
( 6 ) Development of the shoot.634 
f) Discussion ol dry weights .......... 636 
(") - ratio.636 
Root 
/ 3 . The effect of adding boric acid at different stages of growth ..... 638 
{a) General type of recovery subsequent to the addition of boric acid . . . 639 
(b) Effect of the concentration of boric acid supplied ...... 640 
7. The effect of removing boric acid at different stages of growth ..... 641 
a) Death subsequent to the removal of boric acid .... . 642 
(b ) Effect of the concentration of boric acid supplied ...... 642 
5 The effect of the removal of the cotyledons on subsequent growth in water culture . 644 
B. Barley .. 645 
a. The effect of different concentrations of boric acid in the nutrient solution . . 646 
(a) Development of the root .......... 646 
(/>) Development of the shoot .......... 646 
/ 3 . Comparison between the effect of boric acid and borax in the nutrient solution, with 
discussion of dry weights in a and 13 ........ 647 
7. Comparison between the effect of boric acid on broad beans and barley . . . 650 
C. Miscellaneous Plants ............. 650 
(a) Phaseolus multijlorus ........... 650 
(b) Phaseolus vulgaris . . . . . . . . . . . *651 
(c) Trifolium incarnatum . . . . . . . . . . .651 
{d) Trifolium repens . . . . . . . . . . . .652 
1 Thesis approved for the M.Sc. Degree, London University. 
[Annals of Botany, VoJ. XXVII. No. CXLV 1 II. October, 1923.] 
