METHODS OF PASTEURISATION 535 



upward filtration, and passed directly into a bottle-filling machine. 

 Clean stoppered bottles are kept in readiness. When filled, the 

 bottles are placed in circles in the cage at the bottom of the 

 pasteuriser. Into the centre of the apparatus is placed the 

 thermometer. The lid is closed down and clamped, and the steam 

 is admitted from below. The temperatures used are 160" F. (or 

 71^ C.) for twenty minutes in winter, and 180' F. (or 82° C.) for 

 twenty minutes in summer. After the elapse of this period, the lid 

 is removed, the stoppers of the bottles are fixed down, and hot 

 water is admitted into the floor of the apparatus. To this hot 

 water is slowly added cold water, and in about forty minutes the 

 pasteurised milk has been cooled down, and is ready for use in 

 the wards. The apparatus is readily cleansed after use, and the 

 various parts, including the bottles, stoppers, etc, are cleaned 

 daily.^ A somewhat similar apparatus is in use by a Health 

 Association at York,- which has recently started (1903) the York 

 Infants' Milk Depot, after the manner of the Liverpool and Batter- 

 sea system. The apparatus provided for this work is one of the 

 latest construction. It consists of an ordinary oval cylinder dis- 

 infecting chamber, having doors at both ends. The apparatus is 

 lagged, and with outside steel casing, provided with a steam 

 distributor inside, steam gauge, safety valve, thermometers, etc., 

 ready for steam supply from boiler. In connection with this 

 apparatus there is also provided a trolley of convenient size upon 

 three wheels, together with a steel frame holding three separate plat- 

 forms, which can be taken apart to suit bottles or vessels of larger 

 sizes. This frame is mounted also upon wheels running in grooves, 

 and channels are fitted inside the steriliser to correspond. The steam 

 rises around the bottles from the bottom of the cylinder. The trolley 

 is fitted for both ends, and when duplicated a " charge " can be taken 

 from one end of the apparatus, and a fresh one inserted at the 

 other. This apparatus can be used as a steriliser or a pasteuriser. 



A second kind of method is typified in what is known as 

 Lawrence's pasteuriser. This consists of a vessel with fluted walls, 

 over the outside of which flows a thin layer of milk, whilst 



* This apparatus was constructed by L. de Wyttenbach, Torrington Square, 

 London, W.C. 



- The York Heahh and Housing Reform Association, established 1901. 

 Secretary, Miss Hutchinson, 63 Gillygate, York. Apparatus by Wyttenbach : 

 A central depot in Gillygate, and branch depots elsewhere in the city. For 

 conditions controlling source of milk used by the York Societ\-, see Appendix T, 

 p. 596. 



