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

The first indication that phosphorus is important for life came from the
experience that plants