genuine. But even in these cases it is open to the vendor
to show, if he can, that the deficiency was due to natural
causes or to unavoidable circumstances. The courts have
held that when deviations are the result of negligence or
ignorance the vendor is nevertheless liable to punishment.
Thus, when a vendor omits to stir up the contents of a pan
so as to prevent the cream from rising to the top, he may be
punished, if by such omission the milk becomes altered in
composition so as no longer to comply with the regulations;
or, when a farmer allows an undue interval between the milkings
whereby the composition of the milk may be affected, he may
be liable for the consequences. As the limits embodied in
the milk regulations were necessarily fixed at figures lower
than those which are usually afforded by genuine milk, and
as it is a comparatively simple matter to ascertain the
percentage of fatty and non-fatty solids, a strong tendency
exists to bring down commercial milk to the low limits
of the regulations without coming into collision with the
law. The fat of milk is its most valuable and most important
constituent. The exact determination of the percentage of
fat is therefore the chief problem of the milk-analyst.
All analyses made prior to the year 1885 are more or less
inexact, because a complete separation of the fat from the
other milk constituents had not been obtained. In that
year M. A. Adams, by the simple and ingenious expedient of
spreading a known volume of the milk to be analysed upon a
strip of blotting-paper and extracting the paper, together
with the dried milk, by a fat solvent, such as ether or
benzene, succeeded in completely removing the fat from the
other constituents. Since that time simpler and more rapid
means have been based upon centrifugal separation of the
fat. When a measured quantity of milk is mixed with strong
sulphuric acid, which dissolves the casein and other nitrogenous
constituents of the milk, but leaves the fat-globules quite
untouched, the latter can easily be separated in a centrifugal,
in the form of an oil the volume of which can be ascertained
in a suitably constructed and graduated glass vessel, and thus
the percentage ascertained very rapidly and accurately; such
centrifugal contrivances constructed by H. Leffman, N. Gerber
and others are now in general use in dairies, and cheese and
butter factories. The amount of ``total solids'' contained in
milk, that is to say, of all constituents other than water, is
speedily ascertained by evaporating the water from a measured
or weighed portion of milk and drying the residue obtained
in a water-oven to constant weight. By subtracting from the
percentage of total solids that of the fat the amount of ``solids
not fat'' results, and by cautiously burning off the organic
substances, the salts or mineral matters are left. When the
percentage of ``solids not fat'' is less than 8.5 a simple
proportion sum suffices to show what percentage of water must
be present to reduce the ``solids not fat'' to the amount
found. As the added water also reduces proportionately the
percentage of mineral matter natural to normal milk (about
0.71 to 0.73%), the determination of the ash affords valuable
assistance to the analyst. When the amount of ash is higher
than normal, tests must be made for borax, soda or other
mineral matters that are often added as preservatives or acid
neutralizers. Borax is easily tested for by dissolving the milk
ash in a drop or two of dilute hydrochloric acid, moistening
a strip of yellow turmeric paper with the solution and drying
it, when, in the presence of even very minute quantities of
borax, the yellow colouring matter of the turmeric paper will
be changed into a brilliant red-brown. Formaldehyde (which
in 40% water solution forms the formalin of commerce) in milk
affords a bright purple colour when the milk containing it is
mixed with sulphuric acid containing a trace of an iron salt.
Condensed milk is milk that has been evaporated under
reduced pressure with or without the addition of sugar.
Generally one part of condensed milk corresponds to three
parts of the original milk. There is no case on record of
adulteration of unsweetened condensed milk, but sweetened
milk has in the past been frequently prepared either
from machine-skimmed or partly skimmed milk and sold as
whole-milk. As sweetened condensed milk is largely used by
the poorer part of the population for the feeding of infants,
and as the fat of milk is, as stated before, its most valuable
constituent, this class of fraud was a particularly mischievous
one, and led to the inclusion in the Food Act of 1899 of a
special proviso that every tin or other receptacle containing
condensed, separated or skimmed milk must bear a conspicuous
label showing the nature of the contents. As the bulk of
condensed milk consumed in England is imported from abroad,
the customs authorities now exercise a strict supervision over
the imports, and object to the importation of such condensed
milk as contains less than 9% of milk-fat. The average
composition of sweetened condensed milk may be taken, with slight
variations, to be: water 24.6%, fat 11.4%, casein and albumen
10%, milk-sugar 11.7%, cane-sugar 40.3%, mineral matters 2.0%.
Cream.--There are not any regulations nor official standards
relating to this article, the value of which depends upon its
contents in fat. Good stiff cream obtained by centrifugal
skimming may contain as much as 60% of milk-fat, but generally
dairymen's cream has only about 40%. On the other hand, milk
that is abnormally rich in fat is in some places sold as
cream. Attempts to compel dairymen to work up to any stated
minimum of fat have failed, the English courts holding that
cream is not an article that has any standard of quality, but
varies with the character of the cows from which the milk is
obtained and the food on which they are fed. Therefore, as
regards the most important portion of cream, the amount of
fat, adulteration does not exist unless there is a substitution
for the milk-fat by an emulsified foreign fat, but cases of
this description are exceedingly rare. On the other hand,
such additions of foreign materials, like starch paste or
gelatine, which have for object the giving of an appearance
of richness to a naturally poor and dilute article, are not
uncommon. While formerly the sale of cream was entirely in
the hands of milkmen, there has been of late a tendency to
regard cream as an article coming within the range of grocery
goods. To enable this perishable article to be kept in a
grocery store it has to receive an addition of preservative, as
a rule boric preservative, in excessive amount. The purchaser
may take it that all cream sold by others than milkmen, and
much of that even, is thus preserved and should be shunned.
The limit of boric preservative that might be permitted,
but which is nearly always exceeded, is one-quarter of 1%.
Butter.---Of all articles of food butter has most fully
received the attention of the sophisticator, because it
is the most costly of the ordinary articles of diet, and
because its composition is so intricate and variable that its
analysis presents extraordinary difficulties and its nature
exceptional and various opportunities for admixture with foreign
substances. It is the intention of the producer of butter
to separate the fatty portion of the milk as completely
as is practicable from the other constituents of the milk
without destroying the fat-globules. This can only be done
by churning. by which operation the milk-globules are caused
more or less to adhere to each other without losing their
individual existence. Owing to this subdivision of the
fat, and perhaps to the composition of the fat itself, butter
is a more digestible fatty article of food than lard or
oil. It is not possible by mechanical means to remove the
whole of the water and curd of the milk from the butter;
indeed ``overworking'' the butter with the object of removing
the water as completely as possible ruins the structure
to such an extent as to make the product unmerchantable.
In well-made butter there are contained about 85% of pure
milk-fat, from 12 to 13% of water, and 2 or 3% of curd and
albumen, milk-sugar or its product of transformation--lactic
acid,--and phosphates and other milk-salts. In some kinds of
butter, Russian for instance, the percentage of water is rather
less. Generally, by churning at a low temperature, a drier,
at higher temperatures a wetter, butter is obtained. The
curd must be got rid of as completely as practicable if
the product is to have reasonable keeping properties. To
prevent rapid decomposition salt in various quantities is
added. Considering that 100 lb. (10 gallons) of milk yield
only from 3 1/2 to 4 lb. of properly made butter, it is obvious
that a great inducement exists to increase the yield either
by leaving an undue proportion of water or curd, or by adding
an excessive quantity of salt. In some parts of Ireland the
butter is worked up with warm brine into so-called pickle
butter, whereby it becomes both watered and salted in one
operation. Until lately, when the English Board of Agriculture
fixed a limit of 16 for the percentage of water that may
legitimately be present in butter, this kind of debasement could
not easily be dealt with, but even now, where a legal water-limit
exists, the addition of water either as such, or in the shape
of milk or of condensed milk, is very commonly practised,
more or less care being taken not to exceed the legalized
limit. It is obvious that there is an ample margin of profit
for the mixer who starts with Russian butter containing 10%
of water and works it up with milk, fresh or condensed, to
16%, all the other milk-constituents, namely, sugar, curd and
salt, thus introduced counting as ``butter'' in the eyes of the
law. A very considerable number of butter-factors in London
and in other parts of England thus dilute dry butter and
consider this a legitimate operation so long as they keep
within the legal water-limit. Nay, they may even exceed this,
if only they give to their adulterated article a euphonious
name, which, while legally notifying the admixture, raises
in the mind of the ignorant purchaser the belief that he
is purchasing something particularly choice and excellent.
``Milk-blended butter,'' with as much as 24 or more per cent
of water and as little as 68% of fat, is still largely sold
to purchasers who think that they are obtaining extra value
for their money; several attempts to deal with the scandal by
legislature having led to no result. The introduction of water
into butter is also practised on a large scale in the United
States, where a branch of trade in ``renovated'' butter has
sprung up. In the States a considerable quantity of butter
is produced by small farmers, and by the time the product
comes into the market the addition of chemical preservatives
to prevent decomposition not being permitted--the butter has
so much deteriorated in quality that it fetches a very low
price. It is bought up by factors, the fat melted out and
washed, then again worked up with water and salt, care
being generally taken to leave about 16% of water in the
product, which finds a ready sale in England. It may here
be pointed out that England imports an enormous quantity of
butter from the continent of Europe, the colonies, Siberia
and America, the imports, less exports, averaging during
1903-1906 no less than 203,300 tons annually, and the total
