20 
MANGANESE DEPOSITS OP INDIA : INTRODUCTION. 
[ Part I : 
whitish juice exudes, which rapidly turns first brown and then black on 
exposure to the air. This latex consists of laccase, laccol, and water. 
The laccase is in solution in the water and the laccol is in a finely divided 
state as an emulsion. The experiments show that the laccase contains 
manganese and that the latter acts as a carrier of oxygen from the 
atmosphere to the laccol. Laccol is not present in aU plants, but its place 
is very often taken by analogous chemical substances such as tannin, 
boletol, and hydroquinone. It appears from these experiments that the 
presence of manganese is in all probability not fortuitous, but of vital 
importance to the plant, and connected with the extraction of oxygen from 
the air, whenever this is necessary for the causation of various chemical 
changes necessary to the vital activity of the plant. 
Since all animals Uve either directly on plants , or directly or ultimately 
on other animals that eat plants, one would 
Manganese m^the animal ^^p^^^ manganese to be found in animal tissues. 
This is found to be the case ; but the presence of 
manganese in the animal kingdom does not seem to have been so 
thoroughly investigated as in the case of the vegetable kingdom. 
Bertrand, in the paper already mentioned, mentions its detection by 
VauqueHn in hair, Berzelius in bone, Chevreul in mutton grease, - 
Oidtmann in the liver and human spleen ; whilst, according to Millon, 
du Buisson, and Riche, it occurs in small quantities, namely 1 to 5 
milligrammes per kilogramme, in the blood of human beings and 
other mammals. The proportion of manganese to iron in the human 
body is said to be 1 to 20 i. 
1 Penrose, loc. cil,, p. 2. 
