There may arise cases where pasteurizing even of certified milk may be desirable, namely, when from necessity it must be kept for a considerable period before use, as on shipboard, and other places inaccessible to a daily supply of fresh milk. Pasteurizing is also justifiable in miscellaneous milk supplies, the origin of which is unknown. It is safer, by far in this case, to pasteurize than take the chance of consuming pathological germs. =Pasteurizing of Milk.=--A convenient method of pasteurizing milk is recommended by the Dairy Division of the Department of Agriculture, which is as follows: =Directions for the Pasteurization of Milk=.[20]--The pasteurization of milk for children, now quite extensively practiced in order to destroy the injurious germs which it may contain, can be satisfactorily accomplished with very simple apparatus. The vessel containing the milk, which may be the bottle from which it is to be used or any other suitable vessel, is placed inside of a larger vessel of metal, which contains water. If a bottle, it is plugged with absorbent cotton, if this is at hand, or in its absence other clean cotton will answer. A small fruit jar loosely covered may be used instead of a bottle. The requirements are simply that the interior vessel shall be raised about half an inch above the bottom of the other, and that the water shall reach nearly or quite as high as the milk. The apparatus is then heated on a range or stove until the water reaches a temperature of 155 degrees Fahrenheit, when it is removed from the heat and kept tightly covered for half an hour. The milk is rapidly cooled without removing it from its containers and kept in a cool place. It may be used any time within twenty-four hours. A temperature of 150 degrees maintained for half an hour is sufficient to destroy any germs likely to be present in the milk, in cold weather, or when it is known that the milk reaches the consumer soon after milking, and it is generally safe to adopt this limit. It is found in practice that raising the temperature to 155 degrees and then allowing the milk to stand in the heated water for half an hour insures the proper temperature for the required time. If the temperature is raised above 155 degrees the taste and quality of the milk will be affected. [20] By Dr. De Schweinitz.