less frequently than is imagined. Even the
variations may be imaginary. The proportion of
water contained in milk can be ascertained.

For the means of detecting the adulteration
of milk, the reader is referred to Itassall's
Adulteration Detected, in English, and Bouchardat's
Lait, in French. The easiest teat is its
specific gravity, which in genuine cow's milk has
an average of about 1.030 (water being 1.000).
It is frequently several degrees lower, but it
seldom exceeds 1.031. The variation in the
specific gravity of milk is caused by corresponding
variations in the quantity of cream or butter
present. The butter of milk being so much
lighter than water, the greater the proportion of
butter, the lighter, of course, is the milk. Pure
milk, therefore, not deprived of its cream, has a
less specific density than skimmed milk, the difference
being caused by the lightness of the cream.

Many people imagine that flour, chalk, starch,
and the brains of calves or sheep, are intermixed
with skimmed milk to imitate the absent cream.
Such unpleasant suppositions are happily unfounded
in the majority of instances. Dr.
Hassall never met with those substances in milk;
although Professor Queckett had in his possession
drawings made from samples of adulterated milk,
showing the presence of both starch and cerebral
matter. A dishonest practice, sometimes resorted
to, is to remove part or the whole of the
cream, and mixing the skimmed milk with a portion
of fresh milk, to sell the mixture as pure
whole milk. It is rare that anything else is
added than water and bi-carbonate of soda, professedly
to make the milk keep. Carbonate of
magnesia is also employed to make cream keep.
The worst specimen examined by Dr. Hassall
contained fifty per cent, or one-half water. In
the Jura, and other parts of Switzerland, Gruyère
cheese is made in partnership. Each partner
contributes new milk, and the produce is manufactured
in common; which explains the magnitude
of those cart-wheel cheeses. No skimmed
or watered milk ever shows itself there. An
adulterator would be banished and disgraced for
ever. Such examples are of extremest rarity.

But milk is a liquid whose constitution
quickly changes naturally, of itself, and without
any adulteration. It is sensible to the action of
the air, and especially of acids, such as vinegar
and lemon-juice. Mixed with the latter, it
curdles instantly. Rennet affects it in a similar
way. The curd so obtained is pressed into
cheese. Rennet is made from the gastric
juice of animals, but more particularly from
that found in the maws or stomachs of sucking
calves fed entirely upon milk. These maws
are preserved by salting. If the maw be good,
a bit no bigger than a sixpence, put into a teacupful
of water with a little salt, twelve hours
before it is wanted, will suffice to curdle eighteen
or twenty gallons of milk. The quality of
the cheese depends greatly upon the rennet; and
almost every celebrated cheese-making district
has its own receipt for preserving and employing
the maw. Artichoke flowers also curdle milk.

Milk, left in repose, spontaneously separates
into two portions. The cream rises to the top,
and the blue milk remains below. By keeping,
milk turns sour, because its sugar is transformed
info lactic acid. It then curdles. Cow's milk
undergoes the lactic fermentation. Under certain
conditions (not always easy to attain) mare's
milk undergoes the alcoholic fermentation. It
then becomes koumi, a favourite Russian beverage.
The skin formed on the surface of boiling
milk is not cream, but a mixture of coagulated
albumen and cheese; the sediment remaining at
the bottom, is not, as is often supposed, flour
which has been added, but cheesy matter. To
keep milk from turning, a few drops of liquid
ammonia would be better than the bi-carbonate
of soda usually employed by dairymaids.

Railways have been very influential in securing
to large populations a daily supply of good milk.
Before their existence, the graziers round Paris
transformed their cows into milk-machines. Not
contented with the normal quantity of seven or
eight quarts per day; by feeding their cows with
salted fodder and giving them flour and water
instead of green food, and by keeping them constantly
confined in the stable, they contrived
to extract from fifteen to twenty quarts a day
for a couple of years. The milk was rich
in lactine; but the cows became consumptive.
At the least draught of cold air, pneumonia
declared itself, and a dairyman's whole stock
might be dead in twenty-four hours. As an
excess of refinement and ingenuity, cows have
been milked by machinery; but, before pronouncing
on the merits of the system, we should
like to hear the cows' report.

The French have a useful comprehensive word,
"laitage," to express everything which is made
of milk. Thus: The Dutch drive a great trade
in laitage; the food of the Swiss consists mainly
of laitage— which makes some of them look as
if their flesh were cheese, and would turn to
Welsh rabbit, if toasted. Tastes differ in respect
to laitage; which is said to favour the
increase of intestinal worms, if too predominant
in the diet, and taken without salt. The old
rules for a course of milk diet, when to leave
off, and when to go on, are surfeiting even to
read. The canny Scotch shepherd who, having
to drive a flock of ewes to London, lived exclusively
on their milk, to save his board wages,
must have had enough of it by the time he
reached the metropolis. Ewe's milk has been
in high and ancient repute with many tribes.
It was used for the manufacture of cheese, many
centuries before there is any record of this
article of sustenance being made from the milk
of the cow. The famous French Roquefort cheese
is made of ewe's milk. Some people prefer sour
milk to fresh. The Irishman delights to wash
down his potatoes with buttermilk— perhaps
though, because he can get nothing else.
Mare's milk is more pleasant than cow's milk
to Tartar palates. The Arabs drink camel's
milk, either alone or mixed with rice and flour;
their butter is made of goat's or sheep's milk,
which latter, although excelling the milk of the
cow in the quantity of butter yielded, yet that