chlorovinyl-phosphate and is especially
active against the oriental fruit fly.[42]

[Illustration: Figure 22.--ARTHUR KORNBERG (b. 1918) AND SEVERO OCHOA
(b. 1905) shared the Nobel Prize in Medicine and Physiology in 1959.
Kornberg received it for research on the biological synthesis of
deoxyribonucleic acid. In particular, he found that four triphosphate
components and a small amount of the end product as a "template" had to
be present for the enzymatic synthesis. Ochoa received his share of the
prize for research in ribonucleic acid and deoxyribonucleic acid. In
particular, Ochoa synthesized polyribonucleotides and used the
radioactive isotope, P^{32}. The synthetic polyribonucleotides were
found to resemble the natural substances in all essentials.]

Cl H O
| | || OCH_{3}
| | ||/
Cl--C--C--P Bayer's L 13/59
| | \ (Dipterex)
| | OCH_{3}
Cl OH

(CH_{3})_{2}N O O N(CH_{3})_{2}
\|| ||/
P--O--P Schradan
/ \
(CH_{3})_{2}N N(CH_{3})_{2}

Octamethylpyrophosphoramide

[Illustration: Figure 23.--MELVIN CALVIN (b. 1911) received the Nobel
Prize in Chemistry in 1961 for his research in photosynthesis, in which
he specified the function of phosphoglyceric acid as an intermediate in
the synthesis of carbohydrates from carbon dioxide and water by green
plants.]

The story of phosphorus, which began 300 years ago, has acquired new
importance in this century. Many scientists have contributed to it: 13
of them have received Nobel Prizes for work directly bearing on the
chemical and biological importance of phosphorus compounds. In
chronological order, they are: Eduard Buchner, Albrecht Kossel, Otto
Meyerhof, Arthur Harden, Hans von Euler-Chelpin, George de Hevesy, Carl
F. Cori, Gerty T. Cori, Fritz Lipmann, Lord Alexander Todd, Arthur
Kornberg, Severo Ochoa, and Melvin Calvin. The developers of industrial
production and commercial utilization of phosphate compounds have had
other rewards.

Some impression of the continuing growth in this field[43] can be gained
from the following data.

PHOSPHATE ROCK

annually "sold or used by producer" in the United States in million long
tons (2,240 lbs.)

1880 0.2
1890 0.5
1900 1.5
1910 2.655
1920 4.104
1930 3.926
1940 4.003
1945