ii8 



BOTANICAL GAZETTE 



[FEBRUARY 



(MgClj and KCl) in proper proportions. In the mixture 100*=*= MgClj 

 +40*^*^ KCl, the plants were alive and in good condition at the end of 

 twenty days, when the experiment was discontinued. It is evident 

 therefore that in the mixture of magnesium and potassium chlorids 

 the plants live five times as long as in pure magnesium chlorid and 

 three times as long as in pure potassium chlorid. 



TABLE I 



Marine Algae 



All quantities given are cubic centimeters of 0.37SW solutions 



Culture solution 



KCl 



100 KCl I 



40 MgCla S ' 



MgCU 



Distilled water 



Sea water (total salts = 2.7 per cent.) 

 Artificial sea water (total salts = 

 2.7 i>er cent.): 

 100 NaCl \ 

 7.8MgCU / 



3.8MgS04 



2.2 KCl \ 

 I CaCla ' 



Duration of life in 



days : Entero- 

 morpha Hopkirkii 



7 

 20 + 



4 



20+ 

 20+ 



20+ 



The plus agn indicates that the plants were alive at the end of the experiment. 



The results obtained from the study of Vaucheria were even more 

 striking. Zoospores were allowed to attach themselves to slides. 

 These were then rinsed in distilled water and placed in the solutions. 

 The results are shown in the following table and also in fig. i. 



TABLE 11 

 Fresh-water Algae 

 All quantities given are cubic centimeters of .oim solutions 



