108 Agricultural Chemistry. 



Chlorine is found to a considerable extent in the asli of the 

 mangel and other root crops. It exerts beneficial action in some 

 cases when applied as a fertilizer in the form of the sodium salt. 

 Nobbe found that buck- wheat failed to develop beyond the flower- 

 ing stage when lacking a supply of chlorine, and that great ac- 

 cumulations of starch formed in parts of the stems of the plant 

 under investigation. This has led to the view that chlorine, in 

 the form of the sodium salt, is essential to the proper activity of 

 diastase. 



Silicon is abundant in many plants, such as the graminac 

 (grass family, which includes the cereal grains), equisetaceae 

 (horse tails) and the ironwood, cauto and other trees. "Wicko 

 found that the ash of the cauto tree contained 96 per cent of sil- 

 ica: and the ash of the common scouring rush (Equisetuni hye- 

 male) has been found to contain 97.5 per cent of this constituent. 

 This element accumulates in the external tissues of the plant as 

 a constituent of the inorganic compound, silica. Oats, and corn 

 through three generations, have been matured on traces of silicon 

 and this element has been considered generally as unessential to 

 plants. There is considerable evidence, however, that this ele- 

 ment favors economical utilization of small supplies of phospho- 

 rus by plants. 



Of the occasional constituents of plant ash, manganese has been 

 found to be an essential constituent of laccase, an enzyme in the 

 sap of the lac-tree. It is to this enzyme that the setting of lacquer 

 varnish, is due, and its activity has been found to be proportional 

 to the amount of manganese present. The ash of laccase contains 

 as high as 2 per cent of manganese. 



Aluminum occurs in some Lycopodiaceae (club mosses) to the 

 extent of 22 to 27 per cent of the ash. The recent work of Mose- 

 ley on the occurrence of aluminum in certain plants is of great 

 interest. He attributes to this element the cause of the disease 

 known as "milk sickness" or "trembles," which may break out 

 occasionally among dairy cattle and other animals. Moseley as- 

 serts that animals contract the disease when fed tin- white snake 



