The author gives a critical review of the recent work on the subject, and cites some original data. It has been shown repeatedly, by the author and others, that Lemna grows quite well in cultures containing only inorganic nutrients of proper concentrations. Work of the author seems to show that addition of organic compounds does not even stimulate growth, much less is absolutely necessary for health, if a properly balanced inorganic medium is provided. It is concluded that auximones do not exist, in the sense in which Bottom-ley originated the term.