which are allowed to stand for forty-eight hours with
occasional shaking. When the drink is ready for use, a portion (one
fifth to one third) is left in the flask as ferment for a fresh quantity
of milk. The temperature should be maintained at about 18 deg. C., but at
the commencement a higher temperature is desirable. The grains should be
carefully cleaned from time to time and broken up to the size of peas.
The clean grains may be dried upon blotting-paper, in the sun, or in the
vicinity of a stove; when dried in the air they retain their power to
germinate for a long time."

_Leben._--In our earlier references to fermented milks in scriptural
times, we observed that alcoholic fermented milks were not permitted to
be presented at the altar. Such offerings, however, were quite allowable
amongst the ancient Egyptians, the Arabs and Carthaginians,[30] and from
remote antiquity these nations placed great value on this product.
Leben, which is peculiarly associated with Egypt, is a soured milk
prepared from the milk of buffaloes, cows, or goats. It is usually
prepared by the boiling of the fresh milk over a slow fire, after which
some fermented milk from a previous preparation is added to the warm
article, and the fermentation takes place rapidly and is considered to
be complete in about six hours.[31] The Egyptian leben is valued so
highly that it is offered in hospitality to the passing stranger, and it
is regarded as so much of a duty to present this milk, that in some
parts of Arabia it would be looked upon as scandalous if any payment
were received in return.[32]

_Matzoon._--Matzoon is prepared in Armenia in somewhat the same manner
as keffir is prepared in the Caucasus, and indeed it differs very
slightly from keffir in composition. Its use is universal in Armenia.

_Dadhi._--In India large quantities of fermented milk are used, under
the name of Dadhi, and its characteristics are not unlike the similar
products in Europe. The specific bacillus has been investigated by
Chatterjee,[33] who concludes that it is somewhat akin to the _Bacillus
bulgaricus_ and the bacillus of leben (_B. lebenis_). Dr. Chatterjee
gives a resume of his investigations which sums up the whole matter
thus:

"1. The fermented milk of India called Dadhi resembles in all essential
points the Bulgarian fermented milk as well as the leben and other forms
of fermented milk in use in the East.

"2. The causative element of the curdling process