april, 1937.] LOEW & ASO.—ON PHYSIOL. BALANCED SOLUTIONS'. 75 



slow but the chloroplast continued to grow so that it filled 

 out all available space in the cytoplasm and in some cells it 

 grew beyond that causing an irregular form of the spiral by 

 the pressure of growth. 



In the following solution with a relative preponderance of 

 potassa and nitrogen a great deal of protein was formed and 

 stored in the vacuole and cytoplasm, the starch produced by 

 assimilation of carbon being rapidly utilised for that purpose, 

 therefore only little was seen of it in the chloroplast. Growth of 

 the filaments was not very energetic, as phosphoric acid and 

 magnesia were in the minimum. That solution was : 



KN0 3 0.5 per mille. 



Ca(N0 3 ) 2 0.3 „ „ 



MgS0 4 0.05 „ „ 



K 1 H 2 P0 4 0.05 „ „ 



Fe S0 4 trace. 



We have recently also made further observations on the 

 effect of imperfect solutions on Spirogyra nitida, one of the 

 larger species. The concentrations of these solutions were 

 mostly below 0.5 ^ and did in no case reach 1% . A small 

 number of filaments of 6— 10cm. length was placed in lOOcc. of 

 the solutions prepared with water distilled from glass vessels. 

 The temperature varied from 8-22° C. The flasks were exposed 

 to direct sunlight, later on only to diffused but bright day- 

 light. 



The figures in parenthesis in the following table signify the 

 percentage of anhydrous salt; they stand mostly in simple 

 relation to the molecular weights. 



MgSO 4 (0.2) 





Mg(NO s ),(0.2) 



All cells killed in 2-4 days. 



MgCl 2 (0.2) 





