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is taken up by the oat plant in Scotland. Katayama, in Japan, recently showed 

 that manganese has a stimulating effect on oats, barley, rice, &c., and still more 

 markedly on the leguminous plants. Using manganese sulphate to the soil in 

 the proportion of 0-015 per cent., the increase was 50 per cent, in the yield of 

 straw, and 25 per cent, in that of the seeds. Quantities of manganese much 

 exceeding the above tended to decrease the yield. Salomone (" Chem. Centr.," 

 igo6), also proved the beneficial influence of a small quantity of manganese on 

 plants, and the toxic action of large amounts. 



Kayser and Marchand ("Compt. rend.," 1907) have found that small 

 additions of manganese salts resulted in higher proportions of alcohol, glycerol, 

 and organic acids being obtained from a given weight of sugar. Yeasts that 

 have been habituated to comparatively strong solutions of manganese salts by 

 growing in solutions of gradually increasing strength, become exceedingly active, 

 and will induce a more rapid fermentation, and also push it further, especially 

 if a small quantity of a manganese salt is present in the fermenting liquid. 



Several other instances might be mentioned where corresponding results 

 have been obtained, but the above are sufficient to show that small quantities of 

 manganese are undoubtedly beneficial with some plants, and perhaps necessary 

 to obtain the best results with vegetation of various kinds. Whether it is due 

 to an excess or otherwise of manganese in the soil that helps to govern the location 

 of certain species of Callitris, and the Australian Coniferse in general, is a matter 

 for further study and investigation, but that subtle influences are actively at work, 

 governing the growth and distribution of the several species of these genera, can 

 hardly be doubted, and the results so far obtained suggest the idea that the food 

 material of these plants is largely responsible for their distribution. Under natural 

 conditions the selective capabilities of the individual plants appear to be limited, 

 are exceedingly sensitive, and easily upset. It may be, too, that some species 

 are more susceptible to the toxic influences of small quantities of manganese and 

 similar elements than are others. That manganese in small quantity is a common 

 constituent in many plants has been shown, especially by Pichard(" Compt. rend.," 

 1898, 1882-1885), and perhaps it has not yet been proved that these supposed 

 elements of somewhat rare occurrence are non-essential under certain conditions. 

 The common occurrence of an abundance of alumina in Orites excelsa (Smith, 

 " Journ. Roy. Soc," New South Wales, July, 1903) indicates that in this tree, 

 at all events, the element aluminium is an essential constituent, because wherever 

 the tree is grown under natural conditions, alumina is always found in quantity 

 in the ash. Manganese may, therefore, be just as essential to the growth of Callitris 

 species and the other Coniferse of Australia, and its assistance to plant life may 

 be considered to date back to past geological time, as indicated by plates illustrating 

 fossil woods. 



See also article on the oleo-resin of Agathis robusta in this work. 



