Fats are often emulsified for administration to invalids. This is done partly to disguise their taste and partly with the hope of making them more digestible. The taste is undoubtedly improved. It is doubtful if the digestibility is much increased. When oils or fats are needed, it is usually best to give them as cream, butter and bacon, for they are best relished in these forms. The emulsions are sometimes useful additions when they will be taken by patients as medicines and their equivalent rejected as foods.

Oils are often rubbed upon the skin and absorbed from it. They may help to nourish a very weak patient when administered in this way. Olive oil, cacao-butter, and cod-liver oil are the kinds usually employed for endermic administration. Sterilized olive oil may be injected hypodermically. An ounce a day given in this way has been found to lessen nitrogenous waste materially. Its injection does not cause pain. Sterilized grape-sugar will cause intense pain when injected hypodermically. Proteins cannot be sterilized without precipitating them, and, therefore, cannot be injected beneath the skin. There is one exception to this general rule: Serum can be sterilized at 550 C. without precipitating its albumin. It has been given through the hypodermic needle, but the amount of nutriment thus administered is insignificant.