42 
L. A. Boodle. 
Salt or its component elements 1 was found to be present in 
considerable quantity in all the succulent leaves of the wall-flower, 
as will be described below. 
From the method of application of the salt, it seems most 
likely that the salt has entered the plant chiefly through the leaves, 
and not through the roots. Of the small amount, falling on the 
soil at each spraying operation, only a small proportion would reach 
the roots. 
Lesage noted that watering plants with salt was more effective 
in producing succulence than adding salt to the soil. He appears 
to assume that in both cases the salt enters the plant through the 
roots; but, assuming that the leaves were wetted in watering the 
plants, his observation would fit in well with the assumption of 
absorption by the leaves. 
Though in most land-plants absorption of water by leaves is 
probably almost negligeable in proportion to absorption by roots, it 
appears that the leaf, provided it can be wetted, is slightly 
permeable to water (with dissolved salts). a To test the permeability 
of the epidermis in the Wall-flower, leaves attached to the growing 
plant were bent down into beakers containing a watery solution of 
saffranine, and it was found that after three-and-half hours the 
stain had penetrated at a few' points to a considerable depth in the 
mesophyll. The penetration was greater in the succulent than in 
the normal leaf, and in the former the point of entry was often the 
base of a hair, which had been thrown off. 
For comparison with the method of spraying the leaves, 
another experiment w f as made. The soil around one of the original 
control-seedlings w'as heavily watered w'ith salt-solution of the same 
strength as that used for spraying. This was first done July 17th, 
and w r as repeated every time the other plants were sprayed, but 
after three-and-a-half weeks no succulent leaves were to be seen. 
As only one plant was treated in this way, and as one cannot tell 
1 According to Brick (Biol. u. vergleich. Auat. d. baltisckeu 
Strandpflauzen, Schriften d. naturforsch. Gesellsck. in 
Danzig, Neue Folge, Bd. VII., Heft, i, Kef. in Bot. 
Ceutralbl., Bd. 39, 1889, p. 37), and Diels (Stoffwechsel u. 
Struktur der Halopliyten, Pringsheim Jalirb., Bd. 32, 1898), 
the sodium becomes combined with an organic acid in the 
cell-sap in halophytes. 
1 Pfeffer. Physiology of Plants, English Pldition, p. 160. 
Dandeno (Transactions of the Canadian Institute, Vol. VII., 
Part 2, 1902) quotes the literature relating to the al>sorption 
of water and salts by leaves, and describes his own experi¬ 
ments on the subject. 
