EARLY USES 181 CHEMICAL CONSTITUTION OF PHOSPHORIC ACIDS 182 PHOSPHATES AS PLANT NUTRIENTS 185 FROM INORGANIC TO ORGANIC PHOSPHATES 187 PHOSPHATIDES AND PHOSPHAGENS 189 NUCLEIN AND NUCLEIC ACIDS 192 PHOSPHATES IN BIOLOGICAL PROCESSES 197 MEDICINES AND POISONS 198 _Eduard Farber_ HISTORY OF PHOSPHORUS _The "cold light" produced by phosphorus caused it to be considered a miraculous chemical for a long time after its discovery, about 1669. During the intervening three centuries numerous other chemical miracles have been found, yet phosphorus retains a special aura of universal importance in chemistry. Many investigators have occupied themselves with this element and its diverse chemical compounds. Further enlightenment and insight into the ways of nature can be expected from these efforts._ _Not only is the story of phosphorus a major drama in the history of chemistry; it also illustrates, in a spectacular example, the growth of this science through the discovery of connections between apparently unrelated phenomena, and the continuous interplay between basic science and the search for practical usage._ THE AUTHOR: _Eduard Farber is a research professor at American University, Washington, D.C., and has been associated with the Smithsonian Institution as a consultant in chemistry._ When phosphorus was discovered, nearly three centuries ago, it was considered a miraculous thing. The only event that provoked a similar emotion was the discovery of radium more than two centuries later. The excitement about the _Phosphorus igneus_, Boyle's _Icy Noctiluca_, was slowly replaced by, or converted into, chemical research. Yet, if we would allow room for emotion in research, we could still be excited about the wondrous substance that chemical and biological work continues to reveal as vitally important. It is a fundamental plant nutrient, an essential part in nerve and brain substance, a decisive factor in muscle action and cell growth, and also a component in fast-acting, powerful poisons. The importance of phosphorus was gradually recognized and the means by which this took place are characteristic and similar to other developments in the history of science. This paper was written in order to summarize these various means which led to the highly complex ways of present research. The Element from Animals and Plants