6 
RESEARCHES ON THE MANUFACTURE 
growth. The conclusions, the author has drawn from his 
analyses are as follows. 
1) The percentage of water in the leaves continually decreases 
from the spring up to the autumn. 
2) Crude protein and nitrogen-free extract regularly diminish, 
while crude fibre and ethereal extract increase proportionally. 
3) Theine diminishes gradually, while tannin increases 
slightly. 
4) Substances soluble in hot water gradually diminish up to 
a certain period, and then increase slowly. 
5) As regards the quantity of ash, there is but a slight 
fluctuation throughout the year, but its components undergo a 
remarkable alteration ; thus there are a decided diminution of 
potash and phosphoric acid and a considerable enhancement of 
lime, magnesia, and iron ; furthermore the quantities of soda, 
manganese and sulphuric acid increase, while the percentage of 
silica and chlorine remains nearly constant. 
Of the second factor which may alter the composition of the 
leaves i.e. manuring, the only trial ever made, so far as I know, 
is that by J. C. Brown, 1 who made a partial analysis of the tea 
leaves gathered from the plants supplied with a complete fer¬ 
tilizer and others from unmanured plants. This author con¬ 
cluded from his trial, that although the quantity of leaf grown 
on the manured portion of the plot was much greater than on 
the unmanured portion, the leaves, on both portions, contained 
the same percentage of mineral and organic matters. 
Whether the age of the plant may have some influence upon 
the composition of the leaves, is a subject not yet experimented 
upon, although the opinion that older plants produce better 
leaves prevails among our tea-planters. Hence the practice of 
preferring or rather selecting the older plants for the preparation 
of a superior kind of tea, for instance, dew-drops. O. Kellner 
tried in conjunction with M. Tanaka and B. Minari to clear up 
the matter by experimental researches, in which they analysed 
four specimens of young tea leaves gathered at the same time, 
i Journal of the Chemical Society, 1875, p. 1217. 
