1918] TRUE—MARINE ALGAE 81 
2. The osmotic value of the sea water sample calculated from 
plasmolytic experiments was found to be about 22.6 atmospheres. 
This value determined by the freezing point method by GaRREY 
reduced to 22° C. was 23.8 atmospheres. 
3. The osmotic surplus of Cladophora gracilis, Enteromorpha 
intestinalis, and Chaetomorpha Linum was found to be about 6.6 
atmospheres when determined by means of cane sugar, and 11.7 
atmospheres for Cladophora and Chaetomorpha when determined 
by means of NaCl. The penetration of NaCl is supposed to be 
largely responsible for the higher value obtained with this 
salt. 
Bureau OF PLANT INDUSTRY 
WaAsHINcTON, D.C. 
LITERATURE CITED 
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¥ 
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