194 
The Bouche d'Erquy in 1906. 
The Physiological Section concentrated its attention upon 
osmotic determinations of the cell-sap of the halophytes and upon 
the influence of soil factors upon absorption and transpiration. 
In the absence of previous experience at Erquy the time 
available proved all to short to test thoroughly the value and 
appropriateness of different methods in osmosis when applied to 
halophytes. Speaking quite generally the osmotic pressures were 
determined by plasmolysis and were found to rule high as compared 
with ordinary land-plants,—a result fully confirmed when Barger’s 
capillary tube method was employed. Whilst between allied 
species or forms of halophytes, as such, constant differences in osmotic 
pressure do not appear to hold, there is considerable reason for 
suspecting the reverse to he the case with plants from habitats 
characterised by differing salinities. On the strength of these 
indications, therefore, importance attaches to the habitat as the 
determining factor in sap-concentration. In the light of the 
experience gained a full trial will be possible on a future 
occasion. 
The Chemical Section continued the work of last year upon the 
amount and salinity of the water in the soils from the different 
stations and also made several partial analyses of plants of 
differing habitat. In view of the prolonged drought and consequent 
high evaporation it was not surprising to find the soil-water salinities 
ruling much higher than w r as the case last year. In some cases the 
variations in salt-content corresponded with differences in the 
vegetation. 
Regarding the salt contained in the plants themselves, in the 
cases investigated its amount followed generally the salinity of the 
habitat. 
A few sugar estimations were made but they did not confirm 
the conjecture that the red forms would prove richer in sugar than 
the green. The question of colour in halophytes is very interesting 
and attractive, but depends on some subtle combination of factors, 
the nature of which has not yet been reached. 
With the experience of previous years to guide and the great 
convenience of the cottage for the secure storage of apparatus of 
all kinds, organisation was rendered easy. Whilst each section 
had its duties broadly defined in advance so far as the problems 
with which it had to grapple are concerned, there was a con¬ 
siderable margin left to individual initiative—an initiative usefully 
displayed on many occasions during the progress of the work. 
