NATURE 
‘ 
aan 
97 
THURSDAY, JUNE 5, 1873 
CONDENSED MILK 
HE importance of milk as an article of diet is so 
great that anything offered as a substitute for it, 
or that renders it more available as food, demands atten- 
tion. The composition of cow's milk is so nearly like 
woman’s milk that the addition of a little water and sugar 
may be said to convert the one into the other ; hence the 
practice of giving cow’s milk to young children, and 
making it a substantial article of their diet long after they 
have cut their teeth and are able to masticate bread 
and meat. No inconsiderable quantity of milk is also 
consumed by adults, and its nutritive effect is not ex- 
ceeded by any article of diet, as it contains all the consti- 
tuents that are necessary to the perfect nutrition of the 
human body. 
There are, however, several drawbacks in the use of 
cow’s milk which diminish its utility, limit its use, and 
sometimes render it dangerous. One of the great draw- 
backs in milk is its liability to decomposition. The sugar 
it contains becomes acid, the caseine separates in the 
form of curd, and a fermentation ensues which renders it 
unpleasant and sometimes even dangerous as an article 
of diet. The latter effect is seen more particularly in 
young children. During the summer months they suffer 
extensively from diarrhoea, and there is little doubt that this 
is largely due to the acidity of the milk which is given to 
them. Milk bought in the morning in London is fre- 
quently unfit to be used in the evening for the diet of 
infants. These changes in milk are hastened by the pre- 
sent system of bringing milk to London from a distance 
in cans, by which means it is shaken, and its tendency to 
change hastened. 
Another drawback in the use of milk is its liability to 
adulteration. Unfortunately the agent by which milk is 
adulterated, is easily accessible and can be detected with 
great difficulty. We cannot instruct cooks and poor 
people in the use of Jactometers and hydrometers by 
which the learned test milk: moreover, the natural 
liability of milk to vary is very great. Thus the quan- 
tity of cream in milk received by the Aylesbury Con- 
densed Milk Company varies from 9 to 17 per cent. 
Dr. Hassell states that the cream given by the milk of a 
cow, the milk of which he personally inspected, was but 
43 per cent. Although then all milk containing less than 
9 per cent. of cream may be suspected of adulteration, yet 
it may happen that a milk containing but 4} per cent. 
may be really not adulterated with water at all 
This varying quastity of cream also shows that even 
when miik is not adulterated it is liable to great varia- 
tions in the quantity of cream which may be taken as 
the measure of its usefulness as an article of food. 
Many attempts have been made to overcome these 
objections to the use of milk, and from time to time pre- 
parations of it have been sold by which freedom from 
acidity and adulteration are secured. The most available 
of these preparations have been those that submitted the 
milk to a process of evaporation by which more or less 
of the water naturally contained in milk is got rid of. By 
these processes the nutritive constituents of the milk are’ 
No, 188—Volt, vu. 
retained ; the preparation keeps for some time, is easily 
conveyed from place to place, and by the addition of 
water milk, so to speak, is readily manufactured. None 
of these preparations, however, seemed to succeed till a 
process for making what is called “ Condensed Milk” was 
introduced. Whether America or Europe has the honour 
of the invention we need not dispute here. It is now 
made in this country by thousands of gallons daily, and 
its manufacture may be witnessed on a large scale at 
Aylesbury. 
Although the process of evaporating milk may be 
regarded as an exceedingly simple one, the attempt to 
carry it out at Aylesbury on a large scale has developed 
a complicated machinery in which steam power is exten- 
sively used ; 200 persons are employed, and the milk 
of 1,200 cows, each yielding 14 quarts, is daily eva- 
porated. The milk used is brought from farms in the 
neighbourhood in ordinary tin cans. Each can before it 
is sent to the factory is carefully tested by the taste and 
smell and the lactometer. Any doubtful specimens are 
set aside for re-examination or rejection. The milk is 
then passed into a vacuum pan, and the vapour thus.pro- 
duced is carried off and condensed and thrown away. 
When the milk has acquired a proper consistence it is 
mixed with sugar. This addition of sugar is the dis- 
tinguishing feature of the condensed milk process. After 
this the milk is still further condensed till it reaches 
the required consistence, and is run off into the little 
tin cans which are so well known. The whole of 
these operations are carried out with a regard for 
cleanliness, which would look almost fastidious if it 
were not known that a single particle of decomposing 
milk allowed to get into the receiving pans might destroy 
the whole mass. Every can is returned thoroughly 
cleansed to the farmer who sends it, having been first 
submitted to hot water, then toa jet of steam, and then 
rinsed out by a jet of cold water. 
The condensed milk thus prepared is of a semi-liquid 
consistence, and can be taken out of a jar with a spoon. 
Several analyses of this milk have been made. The late 
Baron Liebig found that it contained— 
Wrater™ =. <<. tenes 22°44 
Solids 77°50 
100700 
The Zancet has more recently published the following 
analysis :— 
Moisture . . . . 25°10 
Butter . Chae 11°73 
Gascme.... sen 1517 
Milk sugar. . . . 16°24 
Cane Sugar . . 29°46 
FUSE. 5 ,'s) oma 2°30 
10000 
From these analyses it will at once be seen that the 
only perceptible difference between condensed milk and 
ordinary milk is that the former contains more sugar 
and less water than the latter. Both these things are 
necessary for attaining the objects for which condensed 
milk is manufactured. The diminution of the bulk of the 
water from 87 percent. in ordinary milk to 25 per cent. in 
the condensed secures diminution of the bulk of the milk, 
and thus renders transportation comparatively easy. The 
condensed milk is easily converted to the condition of ordi- 
G, 
