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 careful attention. For the keeping of soured milk, a cold room cooled by a refrigerating machine would be desirable, so as to maintain the fermented milk at a low temperature and prevent over-fermentation. Apparatus has been designed so as to handle soured milk on a large scale, and one of the machines is shown on the illustration (see Fig. 9). It is simply a jacketed cylinder with a cover and an agitating gear. The inside of the machine is nickel-plated, and there is an arrangement whereby the cooling may be done rapidly, through a coil inside the jacket, this coil being connected to the brine circulation of the refrigerating machine. [Illustration: CONTINUOUS APPARATUS FOR THE PRODUCTION OF LARGE QUANTITIES OF SOURED MILK FIG. 9—This apparatus is made by the Dairy Machinery and Construction Company of Shelton, Conn., U S A. The milk is agitated inside a jacketed cylinder, where it is allowed to incubate at about blood heat. The milk can be rapidly heated and also rapidly cooled by means of this apparatus.]