This point is not yet definitely settled. Such heating does not affect the taste of milk and does not render it more constipating. The unfavourable effects; if there are any, are so slight that they need not deter one from the use of pasteurized milk, even for long periods. The preference, however, should always be given to milk which is so clean and so fresh as not to require any heating. _How should milk be pasteurized?_ A convenient form of apparatus is that known as Freeman's pasteurizer[5]; another is the Walker-Gordon pasteurizer.[6] [5] This can be obtained at 411 West Fifty-ninth Street, New York, with bottles and full directions; a tin one, at a cost of $3.50, and a copper one, which is much more durable, for $7.00. [6] Obtained at the same prices from any of the Walker-Gordon milk laboratories. _How should milk be cooled after pasteurizing?_ Always by placing the bottles in cold water, so as to cool them rapidly; never by letting them stand at the temperature of the room, or by placing them, when warm, in an ice box. _Why is this precaution necessary?_ Cooling in the air or in an ice box requires from two to four hours, and during that time a great many of the undeveloped germs may mature and greatly injure the keeping properties of the milk. In the cold water, milk can be cooled in from ten to twenty minutes if the water is frequently changed, or if ice is added to the water. MODIFIED MILK OF THE MILK LABORATORIES _What is "modified milk" of the milk laboratories?_ It is milk containing definite proportions of the fat, sugar, proteids, etc., put up usually according to the prescription of a physician, who indicates how much of the different elements he desires. The most reliable are the laboratories of the Walker-Gordon Company, which has branches in many of the large cities of the United States. This is an excellent method of having milk prepared since it can be done with greater care and cleanliness than are possible in most homes. It is besides a great convenience if circumstances make it impossible to prepare the milk properly at home. The laboratory should be used for infant feeding only by one who is somewhat familiar with this method of ordering milk. PEPTONIZED MILK _What is peptonized milk?_ Milk in which the proteids (curd) have been partially digested. _How is this accomplished?_ By the action of a peptonizing powder which is composed of a digestive agent known as the extractum pancreatis and bicarbonate of soda, which is added to the plain or diluted milk. This is sold in tubes or in tablets, and it is the active ingredient of the peptogenic milk powder. _Describe the process._