April, 1907.] 



LOEW & ASO.— ON PHYSIOL. BALANCED SOLUTIONS. 



77 



K a SO 4 (0.3) + MgSO 4 (0.2) 



All cells healthly for 30 days; half the cells dead after 

 50 days. The living cells have now received nutrients 

 and perhaps also lime from the decaying dead cells, 

 as was clearly evinced by the cell-division taking place 

 here and there. Much starch noticed in these cells, 

 after 60 days. Some rhizoids. 1 ) 



KN O 3 (0.l5) + Mg(NO 3 ) 2 (0.2) 

 (1 Mol. : 1 Mol.) 



Most cells killed in 17 days; the injured cells have 

 living cytoplasm but dead nucleus ; all cells killed 

 after 30 days. 



KNO 3 (0.5)+MgSO 4 (0.2) 

 (1 Mol. : 1 Mol.) 



After 25 days healthy. After 50 days about half the 

 cells killed, while the living cells show swollen nucleus. 

 Chlorophyll body attacked, forming no starch in 

 sunlight, hence probably dead. 



Na 2 S0 4 (0.23) + MgS0 4 (0.2) 



About 10% of the cells alive after 3 days, while 

 without Na a S0 4 all killed in 3 days. 



K NO 3 (0.15j + Ca(NO 3 ) 2 (0.2) 



Most cells alive after 50 days; nucleus normal in all 

 cells. 



K 2 SO 4 (0.3) + CaSO 4 (0.2) 



Many rhizoids had formed. Cells almost all alive after 

 50 days, they have grown in length more than in any 

 one of the cases mentioned here; nucleus in most cells 

 normal but Chlorophyll body often somewhat emaciated, 

 with change of the spiral shape. 



Mg(NO 3 ) 2 (0.2)+Ca(NO 3 )„(0.2) 



Almost all the cells after 50 days perfectly normal and 

 healthy starch present. Very few Chytridia. 



MgSO 4 (0.2)+Ca(NO s ) s (0.4) 



All cells healthy for 30 days, a few filaments injured 

 after 50 days showing emaciated and distrnpted 

 chlorophyll body and displaced contracted nucleus. 

 The healthy cells show starch. 



*) Thus far rhizoid formations were observed by us in solutions containing: 



Ca(NO 3 ) 2 + (NH 4 ) 2 SO 4 (0.002^) 



or CaS0 4 + K 2 S0 4 , 



or MgS0 4 +K 2 S0 4 



but in no case in any of these compounds alone. Sulphates seem to be essential for 



that phenomenon. It deserves to be mentioned that in the numerous cases of imperfect 



culture solutions we observed only in gypsum solution and in 0A% K CI solution that 



the filaments of Spirogyra showed the phenomenon of geotropism. 



Spirogyra sometimes shows the phenomenon of heliotaxis. One of us (L.) has noticed 

 that Spirogyra filaments lying on the bottom of a flask moved with great rapidity into 

 a nearly vertical position, when the first rays of the morning sun reached them. 



