Experiments on Absorption of Salt-Marsh Plants. 131 
period—but this period was interrupted every hour or so for the 
short time necessary to dry and weigh the plant. 
(A). Length of period of immersion, 1^—3 hours. 
The figures obtained from plants immersed in distilled water 
or a 3 % solution of sodium chloride for periods varying in length 
from 1^—3 hours are given in Table VII. Some plants were used 
on two consecutive days, being left in the intervening time in the 
laboratory. Such plants are marked with an asterisk to indicate 
the second day they were used. When immersed in water the 
second day, these plants do not absorb more water than they did 
the first day, though their tissues are not so turgid. The reason 
for this may be that the difference between the osmotic pressure of 
the cell-sap on the two days scarcely affects the ratio existing 
between the osmotic pressure of the cell-sap and that of distilled 
water, and so does not affect the rate of passage of water intothe 
cells. Of the two plants immersed in salt-solution on two con¬ 
secutive days, one absorbed the same amount, calculated per 
gramme of water in succulent per hour ; and the other about three 
times as much on the second day as on the first. The plants 
immersed for two consecutive periods on the same day, show the 
same result, as seen in Table VI, that is that the amount absorbed 
during the first period of immersion is greater that at the second. 
TABLE VII. 
(a.) Plants immersed in distilled water. 
Plant, locality from which it was 
obtained and date of 
experiment. 
Weight in 
grammes 
of 
succulent 
part of 
Dry 
weight in 
grammes 
of 
succulent 
part of 
plant. 
1st period of 
immersion. 
2nd period of 
immersion. 
Increase calcu¬ 
lated as percen¬ 
tage of water in 
succulent part 
Increase 
in weight 
in 
grammes. 
Time: 
Increase 
in weight 
in 
grammes. 
Time: 
of plant at time 
of immersion. 
plant. 
Hours, 
Alins. 
Hours, 
Mins. 
1st 
period. 
2nd 
period. 
Salicornia sp. 
From Erquy, 30/9/’09 (1) 
01780 
0-0125 
0-0085 
2.5 
00025 
1.30 
5-1% 
1-4% 
„ „ l/10/’09 (1*) 
0-1695 
00125 
0-0085 
2.30 
00050 
2.15 
5-4% 
3-0% 
„ „ 30/9/ 09 (2) 
0-1605 
0-0108 
0 0080 
2.0 
0 0045 
1.20 
5-3% 
2"8% 
„ „ 1/10/ 09 (2*) 
01440 
00108 
0-0065 
2.35 
0-0055 
2.0 
4-9% 
3-9% 
