8 
THE FUNCTION OF TANNIN. 
on the assumption that this other product is not itself capable 
of immediate subsequent decomposition or recombination. 
Leaving, therefore, the inherent capabilities of the tannins 
to be discussed by the chemists, I have proposed to myself 
the following :— 
If tannin be a food material , then , like other food materials, 
it will , in case of need , be used as food. 
This I have submitted to experimental evidence by three 
parallel series of investigations. 
(1) Plants, or portions of plants, which from previous 
investigation I knew to richly contain tannin, 
were allowed to grow under such conditions that 
assimilation was impossible. 
(2) Seeds were germinated in darkness, in order to see 
whether the tannin then formed was used up in 
further growth. 
(8) Conns were investigated, in order to see whether 
the tannin which they contained was transferred 
to the newly formed conn, With the transfer of 
the starch. 
Potassium bichromate was used in all these investigations, 
and the preparations made at different times actually com¬ 
pared with one another. The following is a summary of the 
experimental evidence thus afforded :— 
Conn of Crocus. May 28th.—The old conn contained 
starch throughout its tissue, but mostly in scattered “heaps” 
of grains, no cell being full, except near the part of union 
with the new conn, hereafter called the “ union base.” 
Tannin is present in isolated cells, completely filling them 
with a large brown to very dark brown mass, especially 
abundant m the cells near the union base, less numerous as 
you get more remote from this. Many of the conducting 
cells of the vascular bundles are also full. 
The young conn has its cells immensely crowded with 
starch, mostly in small grains. Treated fresh with iron-salt, 
it apparently has no tannin, but potassium bichromate shows 
isolated grains, less frequent than in the old conn, and in all 
cases contained in cells which contain starch. Near the 
union base it also is much more abundant. In the young 
corm the tannin does not fill the cell with one mass, except¬ 
ing in many of the cells near the union base ; but is in the 
form of several small, often irregular, globules or balls. 
June 25tli.—The old corm is shrivelled, and entirely free 
of starch. The distribution of tannin shows no change 
whatever. There is no apparent reduction in quantity. The 
