Statistics of the most economical quantity and quality of food for men in health, and under different conditions of activity, have been very accurately and practically determined, but such data for invalids are in most cases unobtainable, and obviously so, for the condition of individual cases and the severity of diseases are constantly varying, and no definite rules for the exact quantity of food needed could be formulated which would be of general application. For this reason in many hospitals no attempt is made to classify the diet beyond the very elementary subdivisions, consisting, first, of milk diet - i. e., milk alone, or of milk with a little bread, and light farinaceous food; secondly, the "full diet," which is commonly known either by that name or as "house diet" or " ordinary diet." Where no further general classification of the diet is attempted, it is customary to have a supplementary list of foods, usually called "articles of special diet," from which the visiting physician or surgeon is to select appropriate food for individual cases. The expression "low diet," indicating that for the very sick patients, is an unfortunate one, as it may have a depressing sound.

In other institutions, where more care is bestowed upon diet, it is found both convenient and practical to subdivide the diet under several additional headings; the diet under each heading to contain only specially selected and classified foods. This arrangement is to be highly commended, as it not only saves much time and confusion, but is economical to the institution in preventing waste, instead of sending a large number of full diets from the kitchen to the ward, where the lighter or more easily digestible articles are selected for the sicker patients by possibly inexperienced nurses, much of the food being returned uneaten. If the diet is assorted in the kitchen and sent to the ward in a properly classified condition - that is, so many rations of each specified class - there is very much less waste and confusion.

Under this system, the subdivisions which it is found practical and advantageous to adopt are the following:

I. Milk Diet

Milk Diet, consisting of from two and a half to three quarts of milk per diem, and nothing else.

II. Convalescent Diet

Convalescent Diet, or half diet, or light diet, as it is variously called, intended for patients convalescing from acute disease, or for patients who are unable to digest the full house diet. In the average medical ward the majority of patients live usually upon this diet, which is not adapted for the special requirements of any particular disease, but is simply light, nutritious, and easy of digestion, and is therefore serviceable in a very large number of cases which do not need more careful selection of food.

III. Farinaceous Diet

Farinaceous Diet, from which animal food, with perhaps the exception of milk and butter, is excluded. This diet is not of very general use, but is temporarily serviceable in some forms of disease, such as chronic Bright's disease and acute gout.