138 
DOMESTIC ANIMALS. 
different pastures, is estimated chiefly by the quantity of butter con- 
tained in it ; and in this respect some breeds of cows are far superior 
to others. The union of the component parts of milk is chiefly mechan- 
ical, as they separate by subsidence according to their specific gravities, 
the cream being the lightest, and the curd the heaviest ; the curd, how- 
ever, requires a slight chemical change for its separation from the whey, 
which at the same time produces a peculiar acid, called the lactic acid. 
From the moment that milk is drawn from the cow, it begins to be 
affected by the air and changes of temperature, and circumstances almost 
imperceptible to our senses will materially affect its quality ; hence the 
importance of extreme care in every step of the process of the dairy, 
especially in making butter. 
The cows should be milked in the cool of the morning and evening; 
they should not be much driven immediately before milking, and it is 
best to bring them to the place of milking some time before the opera- 
tion begins. In some situations it is better to milk them in the pas- 
tures and carry the milk home ; in others to drive the cows gently to 
the cow-stalls. In mountainous countries the first mode is generally 
adopted, because the cows are apt to leap down steep places, and shake 
the milk in their udder more than is done by carrying it in the pail. 
The same practice holds good in Holland from another cause, which is 
the distance of the pastures from the home-stalls, and the facility of 
transporting the milk in small boats, all the best pastures being sur- 
rounded by small canals communicating with the greater; thus the 
milk may be carried several miles without the least agitation. 
As soon as the milk is brought into the dairy, it is strained through 
a fine sieve or cloth, and it is then poured into shallow pans or troughs 
lined with lead. The best pans are of metal, either of iron, carefully 
tinned, or of brass. Such pans are cool in summer, and in winter allow 
of the application of heat, which is often very useful to make the cream 
rise. When leaden troughs are used, they are generally fixed to the 
wall, and have a slight inclination toward one end, where there is a 
hole with a plug in it, by drawing which the thin milk is allowed to 
run off slowly, leaving the cream behind, which runs last through the 
hole into the pan placed under to receive it. The milk in the pans or 
troughs is generally four or five inches in depth, which is found most 
conducive to the separation of the cream. The place where the milk 
is set should have a thorough draught of air by means of opposite wire 
windows. The sun should be carefully excluded by high buildings or 
trees, and the floor, which should always be of brick or stone, should be 
continually kept moist in summer, that the evaporation may produce an 
equal, cool temperature. A small stove in winter is a great advantage, 
provided smoke or smell be most carefully avoided, and the temperature 
be carefully regulated by a thermometer. In Switzerland men are 
chiefly employed to milk the cows, and in all the process of the prep- 
aration of butter and cheese. The women only clean the utensils, and 
carry green food to the cows when they are kept in the stable. When 
the milk has stood twelve hours, the finest parts of the cream have risen 
to the surface, and if they are then taken off by a skimming-dish, and 
immediately churned, a very de'icate butter is obtained; but in general 
