Vol. LVII. No. 2515. 
NEW YORK, APRIL 9, 1898. 
*1 PER YEAR. 
SPECIAL. DAIRY NUMBER. 
WHAT IS A QUART OF MILK? 
HOW THE COW MIXES IT. 
What It Is; Its Value; Its Life. 
A quart of average milk weighs 2 1-5 pounds, and 
has a specific gravity of 1.032. The quart pictured on 
page 258, contains 87 per cent of water and 13 per cent 
of solids ; of these solids, the fat is lighter than water, 
and the others are heavier. In making this quart of 
milk, the cow took out of the food she had eaten, 1.18 
ounce of fat, 1.18 ounce of casein or cheesy matter, 
1.76 ounce of milk, sugar, and .35 ounce of ash, and 
mixed them with 30.62 ounces of water. This ash rep¬ 
resents all there would he left if the water were all 
evaporated and the solids were all burned. This mix¬ 
ing or manufacture of milk inside of the cow is one of 
the most wonderful operations in all Nature. 
The cow’s udder or bag is a gland, or rather, a pair 
of glands. A gland secretes or takes liquids and 
solids out of the blood as it passes through the body. 
A simple illustration is the saliva or spit which forms 
in the mouth. This comes from glands situated in 
the cheek. When you work your jaws or rub them, 
the saliva pours into the mouth. The smell of a good 
dinner, or even the thought of 
it, will make your “mouth 
water ”. In sudden fright or 
excitement, your mouth and 
lips are dry and parched ; the 
glands do notact. The saliva 
or spit comes from the blood 
through the glands. You 
see" that the mind—the will 
power—has some control over 
the work of the gland. To 
quite an extent, this is true of 
the secretion of milk ; the cow 
can partly control it. When 
she feels well, the flow is best; 
when frightened or ill, she 
can shut it partly off. The 
higher and finer the nervous 
oi-ganism of the cow, the more 
solids she will be likely to 
secrete, and the more quickly 
she will respond to either good 
treatment or abuse. 
Hut what does the udder do? 
Milk is not simply filtered 
blood. The udder does more 
than sift or screen the milk 
out of the blood. It is believed 
that the water, the sugar, the 
ash and a partof thecheesy matter are filtered directly 
from the blood. The fat of the milk is produced in 
the udder. It is really made up of very small parts of 
the cow herself, broken oft' in small cells, and mixed 
with the milk as it passes on. The rest of the casein 
or cheesy matter is also made in the udder. Thus it 
will be seen that the sugar, the ash and part of the 
cheesy matter are dissolved in the water, while the 
fat floats about in the water in fine particles. You 
might compare it, in this respect, with muddy salt 
water which is “ muddy ” because very fine grains of 
soil are floating about in it. 
The udder is not a great bag for holding all the 
milk. A cow that gave 85 pounds of milk in one day 
had an udder that weighed less than 25 pounds. Prob¬ 
ably, when you start to milk, there is never more than 
one-third of the whole milking in the udder. The 
rubbing and pulling at the udder and teats start the 
glands at work, and milk is poured in from the blood, 
just as working the jaws causes the saliva to run into 
the mouth. Prof. Dean, of Canada, says that they 
killed a cow giving a lrrge quantity of milk. The 
udder was cut off and they found that they could still 
draw milk away through the teats; there was a little 
milk already formed there. The cow could not hold 
this milk back, but she could, by exercising her will 
power, stop the formation of more milk to a certain 
extent. You will see from all this, that it is not the 
cow with the most beef or the largest udder that will 
give the best milk. As so much of the milk is made 
during milking, and as the great bulk of the milk 
comes from the blood, a great quantity of this blood 
must be carried to the udder while this process is 
going on. We always look for the cow with great 
milk veins in front of the udder and running far up 
near the heart before they pass out of sight. It will 
interest you to feel of this vein some time while the 
cow is being milked. The water in the milk comes 
from the water the cow drinks. You can’t turn her 
out in the rain and let her soak it in. Muddy or bad¬ 
smelling water might fertilize plants, but it will not 
feed the cow. It will be more likely to make fertilizer 
out of her ! 
The measure of value in milk is the butter fat which 
it contains. It must not be supposed that there is 
only one kind of this butter fat. Butter is really a 
mixture of six or eight distinct kinds of fat, though 
three kinds make up 9-10 of it. These are known as 
olein, stearin and palmitin. The olein is liquid at 
ordinary temperature, while the others are solids. 
Soon after calving, there is a larger proportion of the 
soft olein, while later, or when on dry food, the pro¬ 
portion of the harder fats increases. Of course, as the 
fats are lighter than the other solids, they separate 
from the rest when permitted to stand alone, or when 
whirled in a separator. With slight variations, a 
cow in good health will make milk with pretty much 
the same per cent of fat in it, no matter what she is 
fed. When you see how the fat is put into the milk 
by the cow, you will see how reasonable this is. If it 
were taken out of the blood without any after change, 
of course the richer the food the richer would be the 
milk. Food will affect the character of the milk fat. 
For example, linseed meal will give a soft, oily fat, 
while cotton-seed meal, wheat bran or pea meal give 
a hard, solid fat. 
Milk kept under ordinary conditions is short-lived— 
that is, changes which make it unfit for human food 
rapidly set in if it be left to itself. This is true of all 
very soluble foods—those which contain large amounts 
of water and are loosely put together. When milk is 
first drawn, it is slightly alkaline—the reverse of acid. 
Almost at once, however, the milk begins to change. 
Minute germs which enter the milk after it comes 
from the cow, begin their work, fermentation sets in— 
the milk becomes acid or “ sours The sugar changes 
first, then the cheesy matter, and then the fats. All 
schemes for keeping milk, or prolonging its life, are 
based on the plan of first keeping the bacteria or 
germs out of it, and then keeping it in such condition 
that these germs cannot develop. The stable, the 
cow, the milker, the pail, and the can must all be per¬ 
fectly clean. The germs hide and breed in dirt. As 
the milk comes from the cow, it contains “cowy ” or 
animal odors, which are various gases dissolved in 
the milk. Aeration or airing means blowing these 
gases out of the milk, and this can be quickly done by 
blowing pure air through it, or letting it trickle in a 
thin stream over the surface of a cooler. A cooler is 
a hollow metal box of varying shape. On the inside, 
cold water is kept running, while over the outside, the 
milk runs in a very thin stream. 
The bacteria that sour the milk act slowly in a cold 
temperature. That is why milk, meat and similar 
foods keep so much longer when packed in ice. Heat 
destroys most of the germs. Heating the milk to 
about 152 degrees F., is called 
Pasteurizing it. At the New 
Jersey Experiment Station, a 
cooler is arranged so that 
either hot or cold water may 
be run through it. The milk 
is cooled by running it over 
the cooler while the cold water 
is inside, or Pasteurized when 
the hot water is turned on. 
A quart of milk, when clean 
and pure, is the most natural 
and healthful food that is 
known. A quart of such milk 
as we have pictured is equal in 
food value to 18 ounces of beef¬ 
steak. Whenever milk is 
largely used in any family, the 
bills for meat will surely be 
reduced. The milk business 
is not what it ought to be. Too 
many consumers regard milk 
as a luxury and not as a food. 
The public should be educated 
to know that a quart of good 
milk ranks with meat and 
wheat flour as food. The irroflts 
in the milk business usually 
go to the handlers, because 
milk is short-lived and cannot be kept. Farmers must 
learn how to care for their milk so as to double its 
life or keeping quality, and then combine and find 
more honest handlers. 
To the butter dairyman, the most interesting thing 
about a quart of milk is the part performed by the 
cow in putting the fat into it. The cow’s udder is a 
machine for secreting and mixing fat. Take the ma¬ 
chines in a cotton factory. Turn the whole force of 
the water power on to one machine for a certain time, 
and it weaves 100 yards of cloth. This 'same power, 
turned on to another machine, may result in only 70 
yards. It is the machine, not the power, that is at 
fault. A stream of rich blood passes by or through 
one cow’s udder for 24 hours, with the result that she 
produces three pounds of fat. The same blood force, 
in another cow’s udder, may produce but two pounds. 
It is not the food or the blood that'is at fault, but the 
cow. She lacks the nerve force, the will power—the 
strong maternal instinct needed in every female to 
produce and keep up the special work of the udder. 
We see that the dairy authorities are right in saying 
that the mental qualities of the cow must be looked 
after and considered. 
