Atomic Scheme

In Rochester--city of optical glass, dentists' supplies, kodaks, typewriter ribbons and rich (Eastman-endowed), up-&-coming University of Rochester--the National Puzzlers' League last week met in convention and concocted an anagram: "I, LAITY, CAN CHEER ATOMIC SCHEME." These letters, rearranged, also spell "Oh, Science! May it teach miracle." This puzzling tribute was aimed at a far greater contemporary assemblage of puzzle solvers, the 94th convention of the American Chemical Society, the comings & goings of whose 3,461 delegates made the lobby of Rochester's Hotel Seneca resemble a Manhattan subway at rush hour.

Overgrown Atoms. Headliner of the convention was a round-faced, gum-chewing professor of Columbia University, Harold Clayton Urey, who won a Nobel Prize in 1934 for his spectrographic identification of deuterium, the doubleweight hydrogen atom which in combination with oxygen makes heavy water.

Last week Dr. Urey announced production in experimental quantities of another overweight element -- heavy nitrogen, which weighs 15 units to 14 for ordinary nitrogen. After two years of work he and his associates have produced 20 grams of heavy nitrogen in 2 1/2% concentration, 400 grams of lower concentrations. To obtain it they used a 35-ft. vertical tube designed by Columbia's George B. Pegram for the separation of heavy oxygen. The tube contains 1,200 steel cones. A gaseous compound of ammonia, rich in nitrogen, passes up through the tube; some condenses, trickles down and with each fall from cone to cone the concentration of heavy nitrogen becomes richer.

Heavyweight Detectives. Deuterium occurs in nature to the extent of one atom among 4,500 atoms of ordinary hydrogen. With modern apparatus if deuterium is present in quantities much greater than this proportion it can be detected. Thus if a man weighing 160 lb. drinks 20 drops of heavy water, the excess of deuterium will show in his urine. Biologists have been quick to see that, with two kinds of hydrogen atoms as distinct as red and green, a neat method was available for tracing the course of hydrogen-bearing compounds in body processes. Scientists in Germany have already found by this means that half the water which they drank stayed in their bodies nine days, although some was excreted in 30 min.

As a biological label, heavy nitrogen promises Lo be even more important than heavy hydrogen, since nitrogen is the characteristic constituent of protein foods and their constituent amino acids. With Dr. Urey's heavy hydrogen, Biological Chemist Rudolph Schoenheimer of

Columbia set out to discover what happens in the body to benzoic acid, a nitrogen compound used as a food preservative. In the test acid he substituted heavy nitrogen for ordinary nitrogen. Feeding it to laboratory animals, he found that about 70% of the acid passed through the walls of the intestine combined with glycine and was eliminated by the kidneys.

Using deuterium as a label, Dr. Schoenheimer also made studies of fat metabolism. He found that each animal manufactures its characteristic kinds of fat from, whatever food it takes, even from sugars, proteins and carbohydrates. When '"tagged" stearic acid was fed to mice the tag was disclosed in the oleic and palmitic acids stored in the mouse tissue. Some fatty substances, such as butyric and caproic acids which are abundant in butter, were burnt quickly and completely after they were eaten. Others were stored in the tissue beneath the skin and muscle--but not permanently, a 50% replacement occurring every five to nine days.

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