The Moisture-relations of Terrestrial Algae . 1 
II. The Changes during Exposure to Drought and Treatment 
with Hypertonic Solutions. 
BY 
F. E. FRITSCH 
AND 
F. M. HAINES. 
With eight Figures in the Text. 
Contents. 
TAGF. 
Introduction ............... 683 
A. The general behaviour towards plasmolysing solutions ....... 684 
B. Description of methods adopted in the subsequent investigations and discussion of 
possible sources of error ............ 689 
C. The behaviour when exposed to drought . . . . . . . . .691 
D. The effect of prolonged action of the plasmolysing solution ...... 700 
E. Recovery from the drought condition and the state of the material during drought . . 708 
( a ) Observations on permeability to stains . . . . . . . .710 
(b ) Microscopic characters of drought material ....... 716 
(<:) Observations with dark-ground illumination . . . . . . .718 
( d ) Investigation of centrifugalized material ........ 720 
F. The nature of the granules found in the cells of terrestrial algae . . . . .721 
G. General conclusions ............. 721 
H. Summary ............... 727 
Introduction. 
I N the first paper of this series (Fritsch, 1922 ) it was shown for a number 
of common terrestrial algae that a considerable amount of moisture is 
retained within the cells in the air-dry condition, so that only relatively 
small quantities are requisite to replace that lost by the protoplasts in 
drying. It was suggested that this marked retention of moisture might 
be due to concentration of the sap (loc. cit., p. 39). The observations 
1 From the Botanical Department, East London College. Some of the results of the present 
investigations have already been communicated in abstract (Journ. of Ecol., x, pp. 229-31, 1922). 
[Annals of Botany, Vol. XXXVII, No. CXLVIII. October, 1923.I 
