60 PHYSIOLOGICAL ROLE OF MINERAL NUTRIENTS. 



Molisch has observed, and his observations have been confirmed by 

 the writer, that spores of PeniciUiurri do not even germinate in cul- 

 ture solutions entirely free from magnesia and containing ammonium 

 acetate as the only organic nutrient — a fact which appears very strange, 

 as there is certainly stored up in the spores a sufficient amount of mag- 

 nesium phosphate to make germination and even some further develop- 

 ment possible, and indeed magnesia has been found repeatedly in the 

 ash of fungi spores. The writer has cultivated PenioilUum in a solu- 

 tion containing peptone, tartaric acid, monopotassium phosphate, and 

 0.1 per cent magnesium sulphate, and has convinced himself of the 

 presence of magnesia in the spores/' However, these same spores did 

 not germinate in the solution of ammonium acetate used by Molisch 

 and by the writer, but they germinated in various other solutions, as, 

 for instance, in a 0.5 per cent solution of sodium acetate or of cane 

 sugar containing a small amount of ammonium sulphate. It appears 

 probable, therefore, that a solution containing ammonium acetate as 

 sole organic nutrient is unfavorable for starting in the spores certain 

 processes which render the stored-ap magnesium phosphate available 

 for the beginning of germination. Perhaps there is formed in the 

 spores magnesium ammonium phosphate which is but little soluble 

 when too much ammonia is present in the culture solution. In suitable 

 ■culture solutions, free of magnesia, the magnesium phosphate stored 

 up in the spores may be economically utilized, and even a considerable 

 mass of mycelium may be produced, provided an abundant sowing of 

 spores had taken place. This explains the contradictory results 

 obtained >>y some authors. 



CAN MAGNESIUM SALTS BE REPLACED BY BERYLLIUM SALTS? 



Former attempts to clear up the physiological functions of mag- 

 nesium naturally have raised the question whether beryllium can per- 

 form the functions of magnesium in living cells, since the general 

 behavior of the compounds of both elements bears a strong chemical 

 resemblance. 



ffl It has been shown byAso that the spores of Aspergillus oryza contain a moderate 

 amount of magnesia. The ash of these spores had the following composition: 



Per cent. 



Potash 45. 96 



Soda 4. 13 



Lime 1. 03 



Magnesia 4. 36 



Ferric oxid 4. 91 



Phosphoric acid 39. 64 



Sulphuric acid 2. 00 



Silica 40 



The percentage of ash in the dry matter was 5.15. The fungus had been grown 

 on boiled rice. 



