Fifth, she should have an intelligent conception of the relative nutritive values of different foods, so as to be able to supply a well balanced dietary for the different classes of people who are dependent on her very largely to direct what they shall eat. She ought to bear in mind the fact that the chief value of any food lies in its adaptability to repair the waste of tissue that goes on constantly, and endeavor to supply as far as possible the ideal meal, which is one in which nitrogenous, non-nitrogenous and mineral substances are supplied in the proportion required to repair the waste, and with the minimum tax on the digestive powers. The first qualification really includes three different qualifications—common sense, conscientiousness and justice, for all of which she will have constant need in discharging the duties of her position. Probably in beginning her work she will make mistakes, as every one who accomplishes anything does, but as she buys she will learn to buy, and in no other way. It cannot be learned from books. However, suggestions may be given and accepted that will save the housekeeper from making all the blunders others have made, and save the hospital from the results of total inexperience and lack of knowledge. The amount of supplies of any kind to be purchased at one time will depend somewhat on the demand, but chiefly on the facilities for storing and preserving them. The perishable articles are always the most important, and also the most expensive, and whenever possible she will find that a substantial sum may be saved each month by making cash payments for these articles as purchased. With adequate cold storage arrangements, a month’s supply can be purchased at one time. Hand to mouth, or day to day buying is poor policy for any hospital, though lack of facilities for proper preservation of food often gives the buyer no other alternative. [Sidenote: Bread]