Thus, the study of organic phosphates progressed from the comparatively simple esters connected with fatty substances of organisms to the proteins and the nuclear substances of the cell. The proportional amount of phosphorus in the former was larger than in the latter; the actual importance and function in the life of organisms, however, is not measured by the quantity but determined by the special nature of the compounds. [Illustration: Figure 16.--OTTO MEYERHOF (1884-1951) received one-half of the Nobel Prize in Medicine and Physiology in 1922 for his discovery of the metabolism of lactic acid in muscle, which involves the action of phosphates, especially adenosine duophosphates. (_Photo courtesy National Library of Medicine, Washington, D.C._)] [Illustration: Figure 17.--ARTHUR HARDEN (1865-1940), left, AND HANS A. S. VON EULER-CHELPIN (b. 1875), right, shared the Nobel Prize in Chemistry in 1929. Harden received it for his research in fermentation, which showed the influence of phosphate, particularly the formation of a hexose diphosphate. Euler-Chelpin received his award for his research in fermentation. He found coenzyme A which is a nucleotide containing phosphoric acid.] [Illustration: Figure 18.--GEORGE DE HEVESY (b. 1885) received the Nobel Prize in Chemistry in 1943 for his research with isotopic tracer elements, particularly radiophosphorus of weight 32 (ordinary phosphorus is 31).] [Illustration: Figure 19.--CARL F. CORI (b. 1896) AND HIS WIFE, GERTY T. CORI (1896-1957) received part of the Nobel Prize in Medicine and Physiology in 1947 for their study on glycogen conversion. In the course of this study, they identified glucose 1-phosphate, now usually referred to as "Cori ester," and its function in the glycogen cycle. (_Photo courtesy National Library of Medicine, Washington, D.C._)] The study of this function is the newest phase in the history of phosphorus and represents the culmination of the previous efforts. This newest phase developed out of an accidental discovery concerning one of the oldest organic-chemical industries, the production of alcohol by the fermentative action of yeast on sugar. A transition of carbohydrates through phosphate compounds to the end products of the fermentation process was found, and it gradually proved to be a kind of model for a host of biological processes. Specific phosphates were thus found to be indispensable for life. In reverse, the wrong kind of phosphates can destroy life. As a result, an important part of the new phase in phosphorus history consisted in the study--and use--of antibiotic phosphorus compounds. Phosphates in Biological Processes