Chap. I. ] manganese in vegetable kingdom. 19 
explanation of the presence of the large numbers of concretions of 
manganese oxide that are so abmidantly dredged up in nearly aU deep- 
sea exploration work from the bottom of the ocean i. Manganese is 
also sometimes found in meteorites. 
It is well-known that plants obtain through their roots a certain pro- 
portion of their nourishment by the absorption 
Manganese in the vege- f^.^^^^ ^^ve soU of water containing mineral sub- 
table kingdom. _ . . 
stances in solution. In view of the ease with 
which the manganese minerals are known to imdergo decomposition 
and to pass into solution in surface waters, it is not surprising to find 
that nearly all plants seem to contain a certain proportion of manganese, 
presumably obtained from the soil through the medium of their 
roots. The work on this subject is well summarized by Bertrand 
in the paper already cited 2. It seems that Scheele was the first 
to detect manganese in plants, finding it in the ashes of the wild cummin 
and wood. Later, in 1849, Herapath foimd manganese in the ashes of 
the radish, turnip, beetroot and carrot ; then Richardson found it in the 
ashes of the sugarcane and Salm Hortsdar in those of oats. In 1852 
Liebig detected both iron and manganese in the ashes of tea and coffee. 
Since then the amounts of manganese in many plants have been esti- 
mated, and this element has been recognized as occixrring in potato, 
wheat, grapes, and many other vegetables, fruits, cereals, and wood, 
in addition to those already mentioned. When working in the field on 
the manganese-ore deposits I was not aware of the universal distribution 
of manganese in plants, and collected specimens of wood from trees 
that were growing actually on the manganese-ore, with the idea of 
seeing if they had taken up any manganese. I also collected some 
specimens of bamboo from the top of a laterite hill in the Balaghat 
district in the Central Provinces to serve as a blank so to speak ; for 
this laterite did not contain any visible manganese oxide. I only had 
time to deal with this sample. It was divided into short lengths, 
the outside cut off and rejected, and then 533 • 5 grammes of the 
wood were incinerated in a platinum dish with the production of 8*8 
grammes of ash of a bluish green colour, thus testifying to the presence 
of manganese in the bamboo. In order to find out if manganese is an 
essential constituent of plants and not an accidental one, Bertrand made 
some experiments on the latex of the tree from Tonkin kno\vn as Rhus 
succedanea. It appears that when the bark of that tree is incised a thick, 
1 See especially : — Challenger Re-ports, Vol. on Deep Sea Deposits, (1891). 
2 P. 212. 
C3 
