9 June 1972 5a LVol. 176, No. 4039

LETTERS Radiation Therapy: R. N. Kjellberg; L. G. Jacobs; Water Importation:G. Darrow; Mercury Compounds: E. Arrhenius, G. Lofroth, C. Ramel;M. S. Jacobson; T. W. Clarkson, L. Magos, G. G. Berg; J. K. Miettinen.

Changes in Latin America .......

NEWS AND C

ARTICLES BOMEX: An Appraisal of Results: R. G. Fleagle.............Population and Pollution in the United States: R. G. Ridker ............

Politics of Academic Natural Scientists and Engineers: E. C. Ladd, Jr., andS. M. Lipset ......................................................

Scientists and Surgeons: F. D. Moore ..................................

OMMENT Technology in Ulster: Rubber Bullets Hit Home, Brainwashing Backfires ...........

Katchalsky Killed in Tel Aviv ... ............... ...

Soviet-U.S. Summit: Science Accords Open the Way to Joint ProjectsSmart Bombs: Air Warfare Undergoes a Reluctant Revolution ..................

RESEARCH NEWS

BOOK REVIEWS

Computer-Assisted Instruction: Two Major Demonstrations ...

Beyond Words, reviewed by K. E. Weick; Inner Speech and Thought, K. S. Harris;Influence of Hormones on the Nervous System: B. S. McEwen; DentalMorphology and Evolution, M. C. McKenna; Microtectonics along theWestern Edge of the Blue Ridge, Maryland and Virginia, J. Suppe;Chemisorption and Reactions on Metallic Films, R. L. Burwell, Jr.;Electronic Processes in Non-Crystalline Materials, H. Fritzsche ..

REPORTS Chilean Glacial Chronology 20,000 to 11,000 Carbon-14 Years Ago: SomeGlobal Comparisons: J. H. Mercer .........................................

Oil Pollution: Persistence and Degradation of Spilled Fuel Oil: M. Blumer and J. Sass ..

BOARD OF DIRECTORS

VICE PRESIDENTS ANDSECT1ON SECRETARIES

DIVISIONS

:MINA0;REES GLENN T. SEABORG LEONARD . RIESER DAVID BLACKWELL LEWIS M. BRANSCOMNIRetiringI Presdent. Chairman President; President-Elet RICHARD H. BOLT BARRYCMMONERMATHEMATICSt(A) PHYSICS (B) CHEMISTRY (C) ASTRONOMY (D)John:W:Tukey HerbertFriedman: MartinPaul :: eorgeB. FieldF. A. Ficken RoIf M.Sinclair Leo Schubert Arlo U.Landot

OHLS VOF*nDu SCIENCE (LPS (I SOCIALALDAND. .ECON(OMIC :ASCIENCES (K) HISTORY AND. PHILOSPH ODales B..Harris James S.S Coleman R0ayimotnd3.deegehrnWilliam 0. Gavey fHarvey: Sapolsky: Mond J:.SiegerPHARMACEUTICAL SCIENCES (Np) AGRICULTURE (0) INDUSTRIAL SCIENCE (P) EDUCATION (Q)Linwoddi0 E Tite Roy L.L Loaorn Jcob E. Goldman Lloyd K. JohnsonLinwod F.TicePhillip R. FordyceJohn Autian Michael:0A. Farrell Jordan D. Lewis

ALASKIA DIVISION PACIFIC DIVISION SOUTHWESRN AND RO %M OUTAIN DIVIsIOFGordon 'Harrison Irma Duncan Roy A. Young Robert C. Miller J. :Linton-fGardner Marlowe G. AndersonPresident Executie Secretary President Secretary President ExecutiveSeretar

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AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

Development of Cellular Dependence on Infective Organisms: MicrurgicalStudies in Amoebas: K. W . Jeon ......... 1122

Feeding Produced in the Satiated Rat by Elevating the Concentration ofCalcium in the Brain: R. D. Myers et al.................................... 1124

Spectral Analysis of Variations in Force during a Bar-Pressing Time Discrimination:S. C. Fowler, C. Morgensterni, J. M. Notterman ...................................1126

Calcium Transient in Presynaptic Terminal of Squid Giant Synapse: Detectionwith Aequorin: R. Llinids, J. R. Blinks, C. Nicholson ............................... 1127

Ascent of Sap in Trees: R. C. Plumb and W. B. Bridgman .............................1129

Peyote Alkaloids: Identification in the Mexican Cactus Pelecyphlora aselliformisEhrenberg: J. M. Neal et al . ........................... 1131

Ethanol Oxidation: Effect on the Redox State of Brain in Mouse: A. K. Rawatand K. Kuriyama .................................................... 1133

Age Changes in the Neuronal Microenvironment: W. Bondare)f and R. Narotzky 1135

Cooperative Critical Thermal Transition of Potassium Accumulation inSmooth Muscle: I. L. Reisint and J. Gulati ............................... 1137

Cooperative Thermal Effects on the Accumulation of Potassium and Sodiumin Frog Muscle: J. Gulati and I. L. Reisin .......................................1139

DDT: Inhibition of Sodium Chloride Tolerance by the Blue-Green Alga Anacystisnidiulants: J. C. Battertoni, G. M. Boush, F. Matsumura ...................... .........1141

Morphine-3-Succinyl-Bovine Serum Albumin: An Immunogenic Hapten-ProteinConjugate: B. H. Wainer et al .............................................1143

Crystalline Fraction I Protein: Preparation in Large Yield: P. H. Chan et al. 1145

1,25-Dihydroxycholecalciferol: Metabolite of Vitamin D3 Active on Bone inAnephric Rats: M. F. Holick, M. Garabediani, H. F. DeLuca .......... 1146

Cytochalasin B Inhibits Lymphotoxin Production by Antigen-Stimulated Lymphocytes:M. Yoslinaga, B. H. Waksman, S. E. Malawista .................................. 1147

Auditory Induction: Perceptual Synthesis of Absent Sounds: R. M. Warren,C. J. Obusek, J. M. Ackroff .............................................. .... 1149

Techlnical Comments: Endothelial Projections: H. Wolinsky; U. Smith 11 51

MEETINGS Computer Experiments: P. C. Gehlen, J. R. Beeler, Jr., R. 1. Jaflee; DiseaseTransmission by Arthropods: E. J. L. Soulsby and W. R. Harvey; SpontaneouslyHypertensive Rats: S. Udenfriend and S. Spector; Forthcoming Events 1152

WARD H. GOODENOUGH ECARYL P. HASKINS F

GEOLOGY AND GEOGRAPHY (E)Frank C. WhitmoreWilliam E. BensonENGINEERING (M)Newman A. HallRaynor L. DuncombeINFORMATION ANDCOMMUNICATION (T)

Andrew A. AinesScott Adams

DANIEL P. MOYNIHAN WILLIAM T.PHYLLIS V. PARKINS Treasurer

BIOLOGICAL SCIENCESIan SussexRichard J. Goss

MEDICAL SCIENCES (N)Robert W. BerlinerF. Douglas LawrasonSTATISTICS (U) AlW. Duane EvansEzra Glaser Jo

GOLDEN WILLIAM BEVANExecutive Officer

(FG) ANTHROPOLOGY (H)Richard N. AdamsAnthony Leeds

DENTISTRY (Nd)Joseph L. HenrySholom Pearlman

TMOSPHERIC AND HYDROSPHERICSCIENCES (W))hn A. Knaussouis J. Battan

The American Association for the Advancement of Science was founded in 1848 and incorporated in1874. Its objects are to further the work of scientists, to facilitate cooperation among them, toimprove the effectiveness of science in the promotion of human welfare, and to increase public under-standing and appreciation of the importance and promise of the methods of science in human progress.

COVER

Cross section of pin oak wood (aboutX 5.5). A column of water supportedonly by atmospheric pressure can beonly 10.3 meters high. Sinice treesgrow higher than this, the ascent ofsap in the xylem must be due toanother mechanism. Tension hasbeen assumed to be the mechanism,but a new theory is proposed. Seepage 1129. [From Patterns of Life:The Unseen World of Plants; copy-right 'C 1966 by William M. Harlow;reproduced by permission of Harper& Row]

9 June 1972, Volume 176, Num

AMERICAN ASSOCIATION FORTHE ADVANCEMENT OF SCIENCE

Science serves its readers as a forum for thepresentation and discussion of important issuesrelated to the advancement of science, includingthe presentation of minority or conflicting pointsof view, rather than by publishing only materialon which a consensus has been reached. Accord-ingly, all articles published in Science-includingeditorials, news and comment, and book reviews-are signed and reflect the individual views of theauthors and not official points of view adopted bythe AAAS or the institutions with which the authorsare affiliated.

Editorial Board

ALFRED BROWNJAMEs F. CROWTHOmAS KUHNELLTOrr W. MONTROLL

1972FRKNK PRESSFRANK W. PUTNAMWALTER 0. RoBERTs

1973H. S. GUTOWSKYARTHUR D. HASLERRUDOLF KOM1FNzRDANIEL B. KOSHLAND, JR.

GARDNER LINDZEYRAYMOND H. THOMPSONEDWARD 0. WILSON

Editorial StaffEditor

PHILiP H. ABELSONPublisher Business ManagerWILLIAM BEVAN HANS NusSBAUMManaging Editor: ROBERT V. ORMESAssistant Editors: ELLEN E. MURPHY, JoHN E.

RINGLEAssistant to the Editor: NANCY TEIMOURIANNews and Comment: JOHN WALSH, DEBORAH SHAP.

LEY, ROBERT GILLETTE, NICHOLAS WADE, CONSTANCEHOLDEN, BARBARA J. CULLITON, SCHERRAINE MACKResearch News: ALLEN L. HAMMOND, WILLIAM

D. METZBook Reviews: SYLVIA EBERHART, KATHERINE LIv.

INGSTON, KATHRYN MOUTONCover Editor: GRAYCE FINGEREditorial Assistants: MARGARET ALLEN, ISABELLA

BOULDIN, BLAIR BuRNs, ELEANORE BUTz, RONNACLINE, ANNETTE DIAMANTE, MARY DORFMAN, JUDITHGIVELBER, MARLENE GLASER, CORRINE HARRIS, OLIVERHEATWOLE, CHRISTINE KARLIK, MARSHALL KATHAN,MARGARET LLOYD, JANE MINOR, DANIEL RABOVSKY,PATRICIA ROWE, LEAH RYAN, LOIS SCHMITT, YA LISWIGART, ALICE THEILE

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iber 4039 SCIE:NCE

Changes in Latin AmericaBecause of their significance, we should be aware of happenings in

Latin America. Most of us have read of a population explosion there.Less well known has been a continuing, rapid migration to the majorcities, which is creating social dynamite. At the same time, there havebeen constructive changes, and it is possible that at least some, if notmost, Latin American countries will escape disaster. A basis for hopeis the progress most of the countries are making in education and inchanging the social structure.The changing order in Latin America has given advantages to the

larger countries, as compared with the smaller ones. Countries such asBrazil, Argentina, and Mexico have internal markets of sufficient sizeto facilitate the establishment of industrial capacity, and many plantshave been located there. The larger countries also have a greater varietyof natural resources to draw on. In contrast, a small country such asUruguay is severely handicapped, both as to size of market and as toresources.Of all the countries of South America, Argentina has progressed most.

It has a literacy rate of 92 percent; reproduction is slowing; resourcesare present to provide for a larger population; and industrialization isproceeding. Though support for scientific research has been poor by ourstandards, two Argentine scientists have received Nobel prizes.The most dynamic country in South America today is Brazil. During

the past several years, its gross national product has been growing at therate of about 9 percent; in 1971, it grew 11 percent, and talk of the"miracle of Brazil" has begun. On the average, Brazil is not nearly asadvanced or as literate as Argentina. In the torrid, dry, northeast regionof the country, some 30 million people live in poverty; about half ofthem have a yearly cash income of less than $50. It is in the southern,more temperate region that industry is booming. Production of steel isincreasing rapidly and is projected to reach 8 million tons in 1975.Brazil has begun to export motor vehicles. Last year, several milliondollars' worth of precision parts for aircraft were exported to theUnited States.One of the largest Brazilian efforts has been in education. Resources

devoted to education have doubled during the last 5 years. During thepast 8 to 10 years, the number of students receiving higher educationhas increased by 500 percent. The tradition of education for the fewhas been abandoned.

Brazilians have a flair. The great wholesale food distribution centerin Sao Paulo is unsurpassed in convenience, size, and cleanliness. Itmakes comparable centers in the United States look anachronistic andgrubby. Similarly, their huge international exhibit hall outclasses mostof ours. The big shocker is the new capital, Brasilia. Its construction inthe midst of nowhere has opened up a vast region. Its architecture andthe city plan are highly imaginative and striking.By reason of Brazil's geography, the present dynamism of the country

could have profound consequences on the rest of South America. Brazilborders every country of the continent except Chile and Ecuador, andits neighbors are highly sensitive to the changes that are occurring. Tovarying degrees, they are apprehensive and envious of the Portuguese-speaking giant. But they are more likely to look to Brazil as an examplethan to the United States.

Latin America is on the move. Great changes will be occurring in thenext decades. Some we will applaud. Others we will dislike. In eithercase, we should be aware of the latent power of our southern neighbors.

-PHILIP H. ABELSON