42 



far the defenders of the metabolic theory have given no satisfactory 

 explanation. The writer's above-mentioned theory on the function of 

 lime salts, on the other hand, makes it perfectly clear why strontium 

 salts in certain doses become hurtful and even poisonous for all organ- 

 isms except the lowest forms of algse and fungi. 



POISONOUS ACTION OF MAGNESIUM SALTS. 



If the writer's view that a calcium protein compound participates in 

 the organized parts of the nucleus and chlorophyll body is correct, it 

 might be expected that magnesium salts of the stronger acids would 

 exert a noxious action. The lime as the stronger base would in such 

 a case combine with the acid of the magnesium salt, while magnesia 

 would enter into the place which the lime had occupied in the organ- 

 ized structures, the capacity for imbibition would thereby be altered, 

 and a disturbance of the structure would result which would prove 

 fatal. On the other hand, judging from the laws of the action of 

 masses, it would naturally be inferred that an excess of lime salts 

 would remedy the evil effects by making the reverse process possible. 

 As a matter of fact, a detrimental action is observed when plants 

 are treated with sulphate or nitrate of magnesium in the absence 

 of calcium salts — an etl'ect which is not observed when the same 

 plants are exposed to the exclusive action of calcium, sodinm, or 

 potassium sulphate or nitrate. These phenomena were foreseen by 

 the writer, and may be readily explained by his theory, while the 

 holders of other views have not come forward with an explanation. 



The writer observed that Spirogyra died within four to five days in a 

 1 i>er mille solution of magnesium sulphate, but remained alive for a 

 long time in corresponding solutions of sodium, potassium, or calcium. 

 In a 1 per cent solution of magnesium nitrate smaller kinds of Spiro- 

 gyra will die in from six to twelve hours, but will live a long time in 

 corresponding solutions of sodium, potassium, and calcium nitrate. 

 Spirogyra which had been kept for several weeks in a healthy condi- 

 tion in a solution of 0.1 per mille of monopotassium phosphate in abso- 

 lutely pure distilled water, died within three to four days when 2 per 

 mille magnesium sulphate was added to this solution, but when dipo- 

 tassium phosphate instead of the monophosphate was used death set 

 in much later, that is, after fifteen to eighteen days. 



Some threads of Spirogyra majnscula placed in a solution (1 liter) con- 

 taining 0.02 per mille each of magnesium nitrate and ammonium sul- 

 phate, died in from ten to twelve days, while in the control solution, 

 containing calcium nitrate in place of magnesium nitrate, they were 

 still alive after six weeks, although cell division had stopped completely, 

 and the cells exhibited an emaciated appearance owing to the absence 

 of other mineral nutrients. In still another case threads of the same 

 alga were jilaced in a solution of 1 per mille of magnesium nitrate, while 



