Effort to sell leads to advice from sellers. It takes form in advertisement. Such announcement seeks to secure the response desired, usually purchase of something sold for profit. As the purpose is to commend what is for sale, what can be said in favor of proffered products is said. All facts may not be published, due partly to lack of space, sometimes for other reasons too. Laws guarantee nothing; they only require certain conditions to be maintained.

A manufacturer may state such requirements have been complied with and stop there or he may add what he thinks desirable to be known. Lentils are a chief article of diet of some European workers, as is often advertised. That does not, however, commend their like use where the dietary may be varied by freshly prepared foods as desirable themselves, as are peas and beans, especially if the lentils come canned.

Artificially compounded foods may have only such constituents as are permitted by law, but if what these are and what they come from is not known, no one can be intelligently fed who uses them. That a food of unknown origin serves a cooking-purpose, as a fat that heats without burning, is not enough to know about any food. Science seeks to understand the secrets of nature; these it discloses to humanity for its more competent living, not to compound secret foods for human consumption. What is not said in advertisements is often more important than what is. Ask for this too.

"Pure food" as a trade term means only not adulterated in the eyes of the prevailing law. Legally, "pure food" is not a recommendation; it is only a precaution against foods known to be unsafe; it does not in itself make any food an essentially desirable human food. Desirable foods are legally pure, but also assuredly clean, wholesome, and nourishing.