698 Fritsch and Haines .— The Moisture-relations 
The question still arises as to how far changes might take place in 
material kept damp and merely exposed to the conditions extant in the 
laboratory. There is no doubt that under these circumstances the fila¬ 
mentous forms in some cases tend to exhibit a reduction of the number of 
strongly plasmolysed cells, perhaps as a result of favourable conditions for 
photosynthesis. Thus, in Experiment XII, an estimation of some of the 
original material which had been kept damp afforded on the day of the final 
drought determination 18-2 per cent, strongly plasmolysed, 70-0 per cent, 
slightly plasmolysed, and n*8 per cent, unaffected cells ; but this is quite 
a different result from that obtained with the drought material (cf. Table V). 
In other experiments, however, no such alteration of the original material 
was found ; in Experiment I, for example, an estimation, after 28 days, of 
part of the original material that had been kept damp gave 11*3 per cent, 
strongly plasmolysed, 46-7 per cent, slightly plasmolysed, and 42-0 per cent, 
unaffected cells, a result which does not differ appreciably from that given 
by the material at the outset of the experiment (cf. Table V). 
Table VIII. 
Successive estimations of material of Plenrococcus (habitat II) exposed 
to drought over pure sulphuric acid. 
(Experiment XXVIII, 20 % sea-salt.) 
Date. 
Cells 
counted. 
Plasmolysed. 
Unaffected. 
Dead cells} 
0/ 
% 
0/ 
/O 
Jo 
May 15 
1,000 
67.0 
33 *o 
2 5'4 
„ 16 
1,000 
8.37 
16*3 
11 *6 
„ 1 7 
LLSi 
69-5 
30-5 
9-6 
„ 18 
922 
76-0 
24-0 
18-0 
„ 19 
1,015 
88*2 
ii*8 
8-o 
5 ? 2 2 
1,030 
S6«2 
13-7 
9 * 1 
it 2 3 
1,095 
9 I- 3 
8-7 
8-2 
»> 30 
582 
85-9 
14-1 
9*5 
June 12 
840 
45-5 
54*5 
33*6 
tt 2 9 
641 
61.8 
38-2 
71-8 
The results so far obtained with Plenrococcus and Cystococcus appear 
quite anomalous and difficult to understand (cf. Tables V and VIII and 
Fig. 6). It must remain doubtful whether in these forms there is any 
alteration in the behaviour towards plasmolysing solutions comparable with 
that above described for the filamentous forms, since no really decisive 
results have been obtained. If analogous changes do occur, they certainly 
only ensue after very prolonged and intensive drought over pure sulphuric 
acid. It would seem that in some cases death of the cells intervenes before 
any decisive response to the conditions of drought has taken place (cf. 
1 Cf. loot-note on p, 694. 
