Average of 6 samples Ceylon tea:

Theine--3.29--Increase about 5 per cent Tannin--7.30--
Increase about 25 per cent

Average 12 samples of Indian tea:

Theine--3.73--Increase about 3 per cent Tannin--8.09--
Increase about 20 per cent

W. M. Green reported that in prolonging the steeping of tea from
10 to 20 minutes, he observed the formation of a tannate of theine,
which diminished the proportion of 1.30 per cent. of theine at
10 minutes to 1.16 per cent. after 20 minutes steeping, a loss of
about 10 percent., unless the latter salt so formed is proved to
yield up its theine constituent in the human stomach.

While theine is credited as the source of the most powerful and
useful properties of tea, and without which no plant would be
recognized as tea, yet some of the stimulating or exhilarating
influences of this plant are attributed to the volatile oils
which contribute so largely to the flavors and odors which
characterize tea.

These Essential or Volatile Oils of manufactured tea are said to
reside in the minute cells of the green leaf, but they are
greatly changed by manipulation, for they are not manifest to the
sense of taste or smell when expressed from the green leaf by
bruising, nor does the green leaf yield their aromatic flavors to
an infusion. Professor Johnston says that these precious oils are