IKON AND MANGANESE. 23 



which contained 5 per cent phosphorus and 0.23 per cent iron, and 

 similar substances were observed by Zaleski in the liver of animals, 

 and by Macallum, Stoklasa, and Suzuki in the nuclei of plant cells. 

 Spitzer found in animals oxidizing enzymes, which were nucleoproteids 

 containing- about 0.2 per cent of iron. 



IRON IN FUNGI. 



The question as to whether iron salts are necessary for fungi was 

 formerly answered in the negative. Molisch/' however, observed that 

 even very small traces of iron salts have a great effect upon the growth 

 of fungi, and having discovered traces of it in th \ ash of various fungi, 

 he considers it a necessary element for them. Indeed, slight traces of 

 iron are frequently present in the nutrient compounds used for the 

 cultivation of fungi. Certain writers admit that iron produces a 

 beneficial effect, but deny that it is absolutely necessary. However, 

 Molisch's observation that in fungi iron can not be replaced by nickel, 

 cobalt, manganese, or zinc deserves special consideration. Traces of 

 zinc and related salts will,. according to Raulin, Ono, and Richards, 

 also increase the fungus mass in a given time. Richards has shown 

 that the nutrients are more economically disposed of under this influ- 

 ence. It may also be mentioned here that Gautier and Drouin 

 observed that ferric oxid promotes the fixation of atmospheric nitrogen 

 by soil bacteria. 6 



MANGANESE IN PLANTS. 



Physiologically manganese can not replace iron in plants. Plants 

 have been raised to perfection, moreover, in culture solutions which con- 

 tained no trace of manganese. However, the ash of plants, especially 

 of woody ones, sometimes contains even more manganese than iron. 

 Schroeder calculated for 1 hectare of 80-year-old beech trees near 

 Tharand a content of 104.1 kilos of Mn 3 4 , but only a content of 7.92 

 kilos of Fe 2 3 . 6 ' The ash of Pinus strobus showed a content of 2.06 per 

 cent Mn 3 4 , and that of Pojpulus tremula 1.06 per cent Mn 3 4 (Weber). 



In the case of pines even the pollen grains contain manganese. 

 Ramann found in them 5.23 per cent ash, and in 100 parts of this ash 

 1.95 per cent ferric oxid and 1.12 per cent manganic oxid (Mn 3 4 ).^ 



Recent investigations by the author in conjunction with Messrs. Aso 

 and Sawa show that soluble manganese compounds ma}^ on the one 



a Sitzungsber. d. Wien. Akad., 1892, Vol. CIII. Aso found nearly 5 per cent ferric 

 oxid in the ash of the spores of Aspergillus oryzse. 



&Bot. Jahresber., 1888, p. 29. 



c Wolff's Aschen Analysen, Vol. II. 



^The manganese content in oxidizing enzymes has been mentioned on p. 12. Aso 

 has observed manganese in a nucleoproteid of the tea leaf (Bull. College of Agricul- 

 ture, Tokyo, Vol. IV, No. 4), and Balland in the nucleins of trunks of certain trees 

 (Compt. Rend., 1901). 



