flour, add water to it, and boil it down to the
consistence of thick oatmeal porridge. Then heat separately, in another
vessel, eleven pints of milk to boiling-point, and allow it to cool
down. When its temperature has fallen to 95 deg. F., pour it into a wooden
bowl or tub, and add the boiled flour to it. The upper and open part of
the vessel is then covered with a piece of coarse linen, and left at
rest--at a temperature of about 99 deg. F.--from twenty-four to forty-eight
hours. The appearance of small bubbles, which keep bursting on the
surface of this liquid, combined with a vinous or acid odour, prove that
the ferment is ready. To this fermenting fluid twenty-two quarts of new
milk are gradually (_i.e._, every ten minutes) added, and the whole mass
is continuously beaten up for twelve hours. The temperature during
stirring should never be higher than 94 deg. F. The whole fluid soon begins
to ferment, and after twelve hours a not unpleasant koumiss is ready.
This should be filtered through a horse-hair or muslin sieve, after
which it is fit for drinking. This liquid is called weak koumiss; but a
limited portion of the lactine has undergone the lactuous and vinous
fermentations, and thus the percentage of alcohol is small. Koumiss at
an ordinary temperature remains weak for twelve hours after it has been
beaten up, and then gradually passes into medium.'"

Curiously enough, the richness of cows' milk in fat militates against
its being a good raw material for the making of koumiss, owing to the
production of small quantities of butyric acid, which follows upon the
fermentation, so that it is desirable, if koumiss is to be prepared from
cows' milk, that the fat should be first of all eliminated, so that the
separated milk will then approximate to the composition of mares' milk.

"The chemical changes," says Hutchison,[23] "which take place in the
milk under the double fermentation are not difficult to follow; the
lactic ferment simply changes part of the sugar into lactic acid, the
vinous ferment eats up a very small part of the proteid of the milk,
and, at the same time, produces from the sugar a little alcohol and a
good deal of carbon dioxide; the milk thus becomes sour, it effervesces
and is weakly alcoholic, but the lactic acid causes the casein to be
precipitated just as it does in the ordinary souring of milk, and the
casein falls down in flocculi."

As will have been noticed, it is an essential part of the pr