y modifications of this practice, such as the introduction
of regenerative heaters, so as to utilise a portion of the heat of
pasteurisation, which would otherwise be wasted.

In some cases, again, it is considered necessary to conduct the primary
and secondary cooling over coolers furnished with mantles, so that the
atmospheric bacteria which are everywhere present should be shut off
from the falling milk.

Ordinarily, however, the equipment for a town's dairy consists of:

1. Steam-boiler to generate steam for pasteurising, scalding, etc.

2. Motive power, which may be either a steam-engine, gas-engine, or
electric motor.

3. Refrigerating machine, which is used for supplying cold brine to the
secondary cooler. In many cases it is also used for cooling a room in
which the milk and cream are stored.

4. Milk-receiving tank.

5. Milk-strainer.

6. Pasteurising apparatus, and primary and secondary coolers.

Such a plant is necessary in order to conduct an ordinary town dairy
business in anything like a hygienic way, and is designed only for the
handling of milk intended for domestic consumption.

There are times when another plant might be necessary, such as a plant
for the separation of milk, or for utilising it for the production of
butter or cheese, such operations being subject to the fluctuations in
the milk supply.

It is sometimes desirable also to use up an excess of milk for cheese or
butter-making; hence it is necessary to provide such apparatus as has
been indicated.

_Preparation of Soured Milk._--The foregoing description has been given
in some detail, as showing the ordinary practice, and we now come to
consider how it can be modified so as to provide for the production of
soured milk. It may first of all be premised that within the next few
years the preparation of soured milk as an ordinary production of the
dairy will be universal, and will form a part of the ordinary dairy
practice. The apparatus, therefore, which is necessary is one of
considerable interest to all who are engaged in the dairy industry.

As will be seen from the chapter describing the preparation of soured
milk in the dairy, this process can be conveniently carried on, so as to
utilise the plant which is at present in general use. The milk can be
received in the same way, pasteurised and cooled to about blood-heat,
after which its preparation as soured milk is a very simple matter, and
only requires a certain amount of c