that the sap of the leaf thus liberated from its cells "is
spread all over the surface of the rolled leaf, where it is in a
very favorable position for the oxygen of the atmosphere to act
upon it during the next stage of manufacture, namely,
fermentation." Fermentation, he regards as an oxidation process
mainly.

For the "fermentation" stage, if that controverted term correctly
designates the process, the rolls are either left undisturbed to
heat, or, as in Indian methods, the rolls are broken up, and the
leaves distributed in drawers, with free access of air. In either
case, a spontaneous heating follows, and chemical action is
indicated by a change of color which reddens and darkens the
leaf, and by the evolution of further pleasant "tea" odors. Some
of the tannin is said to be converted into glucose.

Care must be taken, Mr. Crole says, to arrest fermentation at the
proper stage by the first "firing," and this firing expels about
half of the remaining moisture of the withered leaves, and
probably develops an additional portion of those volatile oils
which give fragrance and taste to manufactured tea; and which Mr.
Crole designates by the name of "theol." Too high or too long
continued firing drives off these oils with the watery juices.
They are also wasted by exposure of manufactured tea to the
atmosphere. Firing is sometimes divided into two or three stages.

In the above summary we have described all essential treatment of
tea leaves necessary to produce manufactured tea.

To procure the extreme type of Black teas, a Souchong or Congou,