364 
AMERICAN AGRICULTURIST. 
[September. 
Why Does the Butter Come? 
BY PROP. G. C. CALDWELL, CORNELL UNIVERSITY. 
It is known that the fat in the milk is in the 
form of minute spherical globules, and that 
these being lighter than the surrounding 
liquid, or the milk serum, as it is conveniently 
called, collect mostly at the surface when the 
milk is allowed to stand quietly for a time, 
and that when either this cream or the milk 
is violently agitated so as to throw these 
globules against one another, they stick to¬ 
gether in larger and larger numbers until fi¬ 
nally visible clumps of butter appear. All this 
we know full well; but wise men of science 
and of practice have sought for many years for 
an explanation of these familiar phenomena, 
without being able as yet to find one that is 
in all respects so satisfactory as to meet with 
universal acceptance. 
The oldest theory of any importance, and 
one that is familiar to many, is that each lit¬ 
tle globule of fat is enclosed in an envelope 
or sac of albuminous matter, and that as long 
as these sacs are whole the globules of fat 
will not stick together any more than will 
two pats of butter nicely wrapped up in cloth, 
or two sausages in their skins; but these 
sacs are supposed to be very thin and tender, 
and to be weakened by acids, and that when 
they are knocked together, especially in the 
acid cream, their envelopes soon get worn 
through or torn, and the fat escapes and nat¬ 
urally collects together, while the remains 
of the delicate sacs in the buttermilk make 
it turbid. This explanation is generally 
attributed to a Frenchman, who announced 
it in 1842 ; it looks plausible, for it appears to 
explain many of the phenomena satisfac¬ 
torily ; but the one most serious difficulty 
with it is that so many eminent microscop- 
ists have searched for these sacs or parts of 
them, without being able to identify them. 
When we find all who have the necessary 
experience to enable them to understand 
correctly what they see with it, uniting in 
the declaration that, according to the best of 
their knowledge, the fat globules are not en¬ 
cased in membranous sacs, we can safely 
affirm that the theory lacks its most essential 
foundation stone, and that the question, why 
does the butter come, must be answered in 
some other way. 
A second theory is that the fat globules, 
though entirely bare, are nevertheless so 
closely surrounded in the milk, and es¬ 
pecially in the cream, with a sort of thick¬ 
ened milk serum, that they are kept apart 
until, by being thrown forcibly together in 
the churn or in any other way, the slimy 
layer is momentarily squeezed out from be¬ 
tween them, and they adhere. Soxhlet, 
to whom we owe many valuable con¬ 
tributions to our knowledge of milk, ex¬ 
plains why the butter comes, that has many 
strong points in its favor. Butter fat melts 
at about 90° Fahrenheit; but he takes the 
position, to begin with, that even in cold 
cream the fat is still in liquid form, as it was 
in the warm milk just from the udder—that 
each globule is a globule of a liquid, and not 
of a solid, as might naturally be expected at 
low temperatures. That a substance may 
retain its liquid form at a temperature much 
below that at which it remains solid when 
once solidified, is a well-known physical law, 
and he illustrates it for this particular case 
by interesting examples which I can but very 
briefly notice. Water, if allowed to stand in 
perfect quiet in a cold room may fall to sev¬ 
eral degrees below its natural freezing point 
without freezing; but as soon as the glass 
containing this under-cooled liquid is moved 
so as to agitate its contents, perhaps ever so 
little, freezing follows instantly. Many of 
our readers may have themselves observed 
this phenomenon. When the liquid is divided 
up into very fine particles it is still easier to 
carry it to very low temperatures without 
freezing; and this subdivision may be pushed 
so far that the smallest globules will require 
violent shaking up as well as a low tem¬ 
perature for their solidification. Again, 
it is a well-known physical phenomenon 
that when a liquid is thus divided up into 
very small globules, which are suspended in 
the midst of another liquid with which they 
do not mix, in the same manner as oil will 
remain entirely unmixed with water, these 
globules do not run together as they would 
naturally be supposed to do; on the contrary, 
they resist any attempt to make them unite, 
and are more likely to subdivide still further 
if pressed together. 
It is quite possible, then, for the globules 
of fat in the milk to retain their liquid form, 
even when the milk is very cold; and in re¬ 
maining apart, they only do what any liquid 
globules would do under the same circum¬ 
stances. New when this mass of liquid fat 
globules in the cream, cooled down below the 
temperature at which the fat of which they 
are composed is solid, is shaken up in the 
chum, the same result should follow as when 
the tumbler of under-cooled water is shaken ; 
the globules solidify suddenly, and then they 
adhere when thrown against each other; this 
is Soxhlet’s answer to the question—Why 
does the butter come ? If this is the correct 
answer, then freezing the milk so thoroughly 
that even the fat solidifies should at least in 
part take the place of churning, since the 
first labor of the churning is spent in getting 
the globules into the solid form so that they 
will adhere. Such a result was obtained in 
one experiment by Soxhlet. A quantity of 
milk was divided into two equal parts, one 
which was kept at about 68° Fahrenheit, 
while the other half was completely frozen, 
and then thawed out by putting the vessel 
in water at 68°; both portions of milk were 
then churned as nearly as possible in the same 
maimer in small glass churns, and that one 
which had been frozen was brought in two 
minutes to the condition in which the butter 
was just ready to come, while the other por¬ 
tion required eleven minutes to reach the 
same condition. 
But even this theory, which appears to be 
so fully in accordance with the laws that 
govern the behavior of liquids, and which 
does not seem to assume anything opposed to 
the facts, and was consequently very widely 
approved, is not allowed to have undisputed 
possession of the field. Storck, an eminent 
Danish investigator of milk, does not find 
that the question put at the head of this arti¬ 
cle is satisfactorily answered. His answer, 
however, as well as perhaps an attempt to 
answer that other question which sometimes 
presents itself to the practical dairyman— 
Why doesn’t the butter come ?—must be de¬ 
ferred for consideration until another time. 
Tlie Kentucky Coffee Tree as a 
Ply Poison.— Mr. “ G. F. H.,” Albemarle 
Co., Va., writes us: “Back of our house- 
here, and overhanging the piazza, is a very 
large “ Coffee Tree.” Though this locality is 
infested, like Egypt, with a plague of flies, 
we have never suffered any serious annoy¬ 
ance from them. One year this tree was 
nearly stripped of leaves by a cloud of Potato 
Flies (the blistering fly), and we feared that 
the tree would die from the complete defoli¬ 
ation. In three days, the ground beneath it 
was black with a carpet of the dead corpses,. 
and the tree put out new leaves, and still 
flourishes. For ten years we have used the 
bruised leaves, sprinkled with molasses water, 
as a fly poison. It attracts swarms of the 
noisome insects, and is sure death to them. 
There are, I am convinced, two distinct vari¬ 
eties of the tree. This one rarely bears seed, 
but multiplies by numerous sprouts sent up 
at a great distance from the trunk—often 40 
feet off ; the other is covered with large pods. 
[The staminate and pistillate flowers are on 
separate trees.—E d.] I doubt the efficacy of 
the latter as a fly poison, since several of this 
kind grow about the houses here without 
the beneficial effect having been noticed.. 
The Angora Goat. 
Angora Goats can not bear confinement.' 
indeed a wide range is an essential condition 
to their success. It must be borne in mind, 
that they are omnivorous, so far as vegetable 
growth is concerned, and in flocks must be 
carefully herded, to prevent depredations 
upon cultivated grounds. For this reason, 
island localities are especially suited to this 
industry. Already some of the islands near 
the Pacific Coast have been occupied by- 
goats, and we have no doubt there are many 
islands on the Atlantic Coast that may be 
profitably occupied as goat pastures. 
It is a common impression that the Angora 
and the Cashmere Goat is the same. This 
is a mistake. The animal which furnishes 
the material for the costly shawls of Cash- 
mere is found upon the southern slopes of 
the Himalaya Mountains, near the regions 
of perpetual snow. While the long fleece, 
or “ Mohair,” is the product for which the 
Angora Goat is valued, that of the Cashmere 
Goat is a very fine, downy substance, or 
“shawl wool,” found beneath its thick, 
coarse hair, and known as “ Pashum.” This 
is combed out in the spring, and in the coun¬ 
try where it is produced is, when cleaned, 
worth from $1.50 to $2.00 per lb. But very 
few attempts have been made to introduce 
the true Cashmere Goat into this country. A 
pair was imported in 1848, but the male soon 
died, and it is probable that they can only be 
successfully kept in very elevated mountaiu 
localities. Even could they be acclimatized, 
there is as yet no demand for their product, 
which, in the native country of the animals, 
is only worked up by a tedious process of 
hand labor, which could not be introduced 
in this country. It is probable that when 
the Angora Goat becomes better known, its 
whole value will not be found in its fleece. 
Its flesh is said to be of excellent quality; 
indeed those who have eaten it in California 
say that it is preferable to mutton or venison. 
There is a general prejudice against the flesh 
of the goat which is entirely unfounded. The 
flesh of a kid is quite as acceptable as that 
of a lamb. That of a well fed, year-old ani¬ 
mal, if it has had a free range, is as rich and 
juicy as mutton. The writer, while living 
