SBSULTS OF EXPERIMENTS. 



25 



of the magnesium salts is probably due to the presence of neutraliz- 

 ino- salts in the sea water to which he added the magnesium com- 

 IDOunds, although we are not yet in a position to say that magnesium 

 may not be far less toxic to the AlgtB than to the LeguminosiB or 

 Graminea^. 



To show the relative toxic effect of magnesium sulphate to some 

 of the other salts, Loew " has made some interesting observations, and 

 -tates that Spirogyra died within four or five days in a 1-per-mille 

 solution of magnesium suli:>hate, but remained ali\'e for a long time 

 in corresponding solutions of the sulphates of sodium, potassium, and 

 calcium. Upon the roots of some higher plants the same investiga- 

 tor made similar observations, and says that Vicia and Pisum do not 

 start lateral roots when kept in a solution of 0.5 per cent of mag- 

 nesium sulphate or nitrate, and the root cap and ei)idermal cells die 

 after a few days. Seedlings of Phaseolus placed in a solution of 0.1 

 per cent magnesium sulphate with 0.1 per cent of monopotassium 

 phosphate showed injury to the roots after five days, and the entire 

 plant succumbed soon afterw^ards. 



Coupin '' found during the course of some experiments with wheat 

 that magnesium chlorid was more toxic than magnesium sulphate. 

 He gives the limit for magnesium sulphate at 1 per cent and for mag- 

 uesium chlorid at O.S per cent. 



RESULTS AVITTI jMAGNESIUM CHLORID. 



The following table shows the results obtained for the different 

 varieties with pure solutions of magnesium chlorid : 



"The Pliysiological Role of Mineral Nutrients in IMants. r.ui. 4.",, llnieau of 

 n.iiit Industry, U. S. Depai-tniont of A.!?riculture (19U3). 



'' Sni- la Toxicite (lu Chlorure de Sodium et de I'Eau de Mer a !'IvL,'ard des 

 Vegetaux. Uevue GenOrale de Butanique, lU : ISS (IS'JS). 



