Preservation and adulteration of food are rarely causes of poisoning. Formaldehyd so alters flesh as to deprive it of flavor and renders it impervious to the gastric juice. It likewise retards peptolysis. Canned meats preserved with this agent, while of good appearance and odor, will provoke indigestion and fail to nourish. Benzoic acid, salicylic acid, boric acid, their derivatives and similar preservatives probably do little direct harm as they are usually employed. They may be hurtful, however, if the kidneys are not healthy and do not eliminate them rapidly. They likewise hinder digestion, although most adulterants are harmless. Their employment is generally and rightly condemned: first, because benzoic acid or its salts such as sodium benzoate may prove harmful if it is in many kinds of food commonly eaten because enough may be eaten then to do harm, although only a trifle is obtained from each kind. Especially are children, aged and feeble persons apt to be thus affected. Second, because it is not necessary for the preservation of foodstuffs. The best grades of preserved foods do not contain it or any substitute for it. Third, because when preservatives are used scrupulous cleanliness and extreme care in handling and in selecting foods are not necessary.

These have been deemed sufficient reasons for forbidding the sale of foods preserved with chemical preservatives by almost every government in Europe, as well as by experts and scientific societies in this country.

Once in a while poisonous pigments are mixed with confections and foods, but this is unusual, and in most instances only an accident caused by ignorance. Yet, as was traced by D. D. Stewart,1 an epidemic apparently of some obscure infectious disease, causing fatal convulsions among children in one of the suburbs of Philadelphia, was due to chrome yellow used as 'egg coloring' for cakes and sold to hundreds of bakers by one of the most reputable drug houses in the city. Tin- and lead-poisoning have occurred from eating vegetables that were preserved for many months in tin cans with soldered joints. It is, however, rare that poisoning is produced in this way unless the canned goods have been kept unusually long. It has been shown, however, that sometimes enough tin will be dissolved in three or four months from the inside of a can of asparagus to produce an appreciable effect, provided such food is eaten often and abundantly. Such forms of poisoning have usually been observed in isolated communities where food is kept for very long periods of time - as, for instance, among arctic explorers, among miners in distant and inaccessible places, among sailors on long voyages, and among soldiers who are suddenly assembled in large numbers and cannot at once be supplied with fresh food and meat, and must use whatever can be purchased, no matter how old it may be.

1 "Medical News," June 18, 1887; Third Annual Report of the State Board of Health of Penna., 1888.

All these facts make it evident that intelligent care should be taken in cultivating and feeding plants and animals which are to be used for food, in preparing them for the market, and afterward for the table. Cleanliness is essential at all times.

Idiosyncrasies

Idiosyncrasies lead to the production of discomfort and even to structural changes in some persons when certain foods are eaten that are wholesome for most others. Milk does not agree with every one. Eggs cause acute indigestion in some, and there are many foods that may cause urticaria in certain individuals. Many fruits are obnoxious in one or another way to susceptible persons.