BOTANY: S. C. BROOKS 
571 
diffusion of the salts of sea water in the later periods of an experiment 
was apparently due to injury of the protoplasm by unfavorable condi- 
tions necessarily imposed by the experiment) , and that it was decreased 
considerably by calcium chloride and still more by lanthanum titrate. 
Figure 2 shows that the decrease in permeability due to calcium 
chloride, is temporary. It is succeeded by an increase of permeability, 
which in the case of calcium chloride (as well as in the case of sodium 
chloride, which produces an immediate increase), culminates in a rate 
of diffusion which is the same as that through killed tissue. 
These experiments show that the protoplasm of Laminaria is per- 
meable to inorganic salts, and that characteristic alterations in its per- 
meability are produced by various salts. Sodium chloride causes an 
TABLE 1 
Permeability of Living Laminaria 
f-l 
UPPER 
SOLUTION 
FIRST PERIOD 
SECOND PERIOD 
RATIO 
EXPERIl 
NUMB 
Lower 
solution 
Dura- 
tion 
h. m. 
Change 
per cent 
per hour 
Upper 
solution 
Lower 
solution 
Dura- 
tion 
h. m. 
Change 
per cent 
per hour 
2d PERIOD 
1st period 
18 
1 sea 
water 
sea water 
2.05 
0.73 
\ sea water 
sea water 
2.00 
0.78 
1.07 
19 
\ sea 
water 
sea water 
2.00 
0.79 
NaCl 
0.26 M 
NaCl 
0.52 M 
2.00 
1.11 
1.41 
22 
1 sea 
water 
sea water 
2.04 
0.73 
CaCl2 
0.14 M 
CaCl2 
0.28 M 
2.02 
0.51 
0.70 
17a 
^ sea 
water 
sea water 
1.35 
0.73 
La2 (N03)6 
0.05 M 
La2 (N03)6 
0.10 M 
1.35 
0.33 
0.45 
increase in permeability culminating in death. Calcium chloride 
causes a temporary decrease in permeability, followed by an increase, 
culminating in death. Certain preliminary experiments indicate that 
the great decrease in permeability produced by lanthanum nitrate is 
followed by an increase, presumably culminating in death. 
It was possible to demonstrate by suitable modifications of the dif- 
fusion methods, described above, that the cell walls of the epidermis 
from the inner surface of the bulb scales of the onion are exceedingly 
impermeable to sodium, calcium and aluminium chlorides, sodium hy- 
droxide, eosin and Bordeaux red, and slightly permeable to hydro- 
chloric acid. 
2. The observations of many investigators are best explained on the 
assumption that when cells in equilibrium with the Hquid normally fill- 
