THE BOTANICAL MAGAZINE. 



[Vol. xxr. No. 243. 



MgCl 9 (0.1)+Caa s (0.2) 



About 95 per cent of all the cells after SO days per- 

 fectly normal. 



MgSO, 0.2 +CaSO 4 (0.2) 



All cells normal after 50 days. Later on a yellowing 

 set in. No rhizoids. No parasites. 



Mg(NO 8 ) 2 (0.2)+K a SO 4 (0.01) 

 +Ca(NO 3 ) a (0.04) 



Remaine.l healthy for 32 days, but later on many cells 

 died, and those cells that lived after 50 days showed 

 injury to chloroplast and displaced nucleus. No further 

 starch formation was possible. The effect of a relative 

 excess of magnesia was evident. No rhizoids were 

 observed. 1 ) 



It will be seen from t*his table that the cells remain alive 

 and healthy in solutions of calcium salts at a concentration of 

 0.2% and further that the poisonous action of magnesium salts 

 can onh r be prevented by certain doses of calcium salts. It 

 will be further noticed that potassium salts can retard but not 

 prevent the toxic action of magnesium salts, which influence is 

 more noticeable when both bases (or one of them) are present 

 as sulphates than in other cases. It would be, however, not 

 be justified to give the same explanation for both cases of 

 counteraction without close examination. One might, e.g., 

 suppose that potassium -protein compounds 2j in the living 

 matter can exchange their potassium against magnesium and 

 that this might lead to a similar disturbance as by the sub- 

 stitution of the calcium of the nucleus for magnesium. Such 

 an explanation would demand the proof that the assumed 

 potassium protein-compound forms really on essential part of 

 the tectonic of living matter; it might merely be loosely con- 

 nected with the structural elements and in that case the sub- 



*) It must be not lost slight of in these experiments that a living cell can extract 

 through Ihe separating wall, from a neighboring cell in a dying condition, various 

 compounds of organic and anorganic nature and thus become able to a prolonged 

 resistance under unfavorable conditions. 



-> The existen.ee of such compounds in the living cells was assumed by one of us 

 long ago, cf: '1 he Physiological Hole of the Mineral Nutrients, p. 27, Washington 

 1 390. I>ic chemische Energie der lebenden Zellen I Edition p. 34. The assumption 

 ill o such n protein compound would be necessary for the chemical condensation processes 

 in all cells doei nol exclude Willsatters view on the rdle of Mg in the chlorophyllbody. 



