132 MODERN DAIRY PRACTICE. 



it. In some cases it will prove of advantage to free the 

 water from coarse impurities by means of a sand or animal- 

 charcoal filter. A simple and practical water-filter has 

 been constructed by Paasch in Horsens, Denmark. In an 

 iron cylinder about three feet high and one foot wide were 

 placed six different layers, viz., small pebbles, gravel, sand, 

 charcoal, rusty bits of iron, etc.; the layers were sepa- 

 rated from one another by means of perforated false 

 bottoms. The apparatus is very easily cleaned and kept in 

 order. 



The water used for rinsing vessels in which milk or its 

 products are to be handled ought in one way or another to 

 be made germ-free. If allowed to evaporate in or on the 

 utensils it leaves on them not only all visible impurities 

 it may happen to contain, but also substances invisible 

 to the naked eyes, as bacteria. The special treatment 

 necessary for preventing infection by the water may, in 

 my experience, be of two kinds. The more common way 

 in dairy work is to sterilize the water through boiling be- 

 fore using it; where boiled water cannot be used, melted 

 ice-water with pieces of ice still floating in the same is 

 often applied. 



Sterilization of Water. Both these methods may be 

 recommended for factory purposes. The boiling is done 

 by heating water with steam in clean tin cans after finish- 

 ing the other work of the day; the cans are then covered 

 so that dust cannot get into them, and the water is cooled 

 as rapidly as possible. The majority of the bacteria and 

 spores found in it will be killed by this treatment, and the 

 development and multiplication of the few surviving ones 

 will be checked. 



Use of Ice-water. The method of applying ice-water 



