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SCIENCE, VOL. 133

Warren S. Wooster, formerly associateresearch oceanographer at the Univer-sity of California's Scripps Institutionof Oceanography, has left for Paris,where he will head UNESCO's recentlyestablished Office of Oceanography.The Office of Oceanography was au-

thorized by the UNESCO Council inNovember. At the same time, the coun-

cil set up an Intergovernmental Ocean-ographic Commission. The aim of bothbodies is to foster international cooper-

ative research in the marine sciences.As director of the Office of Ocean-ography, Wooster will serve as secre-

tary of the commission.

Physicist Richard F. Humphreys hasbeen named president of the CooperUnion for the Advancement of Scienceand Art in New York City, effective lJune. He is now vice president of theArmour Research Foundation, IllinoisInstitute of Technology, Chicago. Hum-phreys succeeds Edwin S. Burdell, whoretired in February 1960 to becomepresident of the Middle East Techni-cal University in Ankara, Turkey, after22 years as director and president ofCooper Union.

Wendell M. Stanley, director of theUniversity of California's Virus Lab-oratory, Berkeley, arrived in Europethis month to begin an 8-month studytour on a Guggenheim fellowship.Through visits to laboratories in tenEuropean cities, he hopes to strengthenand extend international scientific co-

operation in the field of virus research.

The following men will lecture at a

number of colleges and universities dur-ing March as Sigma Xi national lec-turers.

Theodosius Dobzhansky, Dacostaprofessor of zoology, Columbia Univer-sity, will discuss "Man and NaturalSelection."Norman F. Ramsey, professor of

physics at Harvard University, willdiscuss "Nuclear Interactions in Mole-cules."Sanborn C. Brown, associate profes-

sor of physics at Massachusetts Insti-tute of Technology, will 'discuss "Plas-ma Physics."

C. Jolliffe, deputy director of theGrants Division of Great Britain's De-partment of Scientific and IndustrialResearch, London, will be in theUnited States and Canada from 28

572

March to 8 May. He is primarily in-terested in the handling of problemsarising from government support ofuniversities and technical institutions.He will visit Washington (30 March-5April, and 4-7 May); Baltimore; Ra-leigh, N.C.; the Boston area; and Ot-tawa and Montreal, Canada.

Among the six women with outstand-ing careers in government selected as

winners of the first annual FederalWomen's Award were two scientists-Charlotte Moore Sitterly, physicist withthe National Bureau of Standards,Washington, D.C., and Rosslyn S. Ya-low, principal scientist, RadioisotopeService, Veterans' Administration Hos-pital, Bronx, N.Y.

At Stanford University School ofMedicine, Thomas A. Stamey, asso-

ciate professor of urology at JohnsHopkins University Medical School,has been appointed associate profes-sor of surgery and will head the new

division of urology in the departmentof surgery. Tag Eldin Mansour, asso-

ciate professor in the department ofpharmacology at Louisiana State Uni-versity, has been- appointed professorof pharmacology.

Maurice J. Murray, chemical consul-tant to the Universal Oil Products Co.,Des Plaines, Ill., has been appointedchief scientist of the U.S. Army Chem-ical Corps. He will report for duty on

1 March. Prior to joining UniversalOil, Murray was professor of chemistryand acting chairman of the depart-ment of chemistry at Illinois Instituteof Technology.

William N. Parkinson, vice presidentin charge of the Temple UniversityMedical Center, is retiring after more

than 35 years of service. Parkinson,who has held various posts at Temple,was for 30 years dean of the MedicalSchool, from which he was graduatedin 1911.

Louis Gordon, professor of chemis-try and a well-known analytical chemist,has been appointed dean of graduatestudies at Case Institute of Technology.The appointment will be effective 1July, when Eric Arnold, at present as-

sociate dean, reaches the mandatoryretirement age for administrative per-

sonnel. Arnold will continue as pro-fessor of chemistry.

James A. Krumhansl, professor ofphysics at Cornell University, has beenappointed director of Cornell's Labora-tory of Atomic and Solid State Physics,succeeding Robert L. Sprouli, who wasrecently named director of the CornellMaterials Science Center.

Lauriston Sharp, distinguished an-thropologist, has been appointed visit-ing professor of anthropology for the1961-62 academic year at the Univer-sity of California, Berkeley. Sharp isan authority on the cultures of South-east Asia.

Recent Deaths

Lyman Allen, Burlington, Vt.; a pastpresident and a founder of the Ameri-can College of Surgeons and emeritusprofessor of surgery at Vermont Col-lege of Medicine; 2 Feb.

Larry R. Commissaris, Tucson, Ariz.;zoologist; was doing graduate work inthe department of zoology at the Uni-versity of Arizona; 17 Jan.

Rev. Dr. Etienne Drioton, Paris,France; 71; archeologist and well-known Egyptologist who was namedhead curator of Egyptian antiquities ofthe Louvre Museum in 1952; workedin Egypt for 28 years, but at the timeof the Egyptian coup d'etat of 1952was dismissed from his posts as direc-tor general of the Department of Egyp-tian Antiquities in the Ministry of Edu-cation and director of the EgyptianMuseum in Cairo; 19 Jan.

Robert H. Kent, Havre de Grace,Md.; 75; physicist and a leader in mod-ern ballistics, who worked at theArmy's Proving Ground BallisticsLaboratory for 34 years before retir-ing in 1956; for many years was chair-man of the explosives and armamentpanel of the Air Force Scientific Ad-visory Board; 3 Feb.Meyer Mendelsohn, New York,

N.Y.; 65; chemical engineer; vice pres-ident of Yardney Chemical, Inc., andhead of chemical research for theYardney International; early developerof ion-exchange separators, used insilver-zinc batteries for missile, satel-lite, and other applications; 14 Feb.

Jerome T. Syverton, Minneapolis,Minn.; 53; professor and head of thedepartment of bacteriology, Universityof Minnesota; distinguished teacher andinvestigator in virology and cell biol-ogy; 28 Jan.

SCIENCE, VOL. 133

scribed and discussed in the presentedition, but the accounts of many timesthat number of other birds have alsobeen revised in keeping with new dataaccumulated since the book was firstpublished. The nomenclature through-out has been revised where necessary

to conform with the latest edition of theCheck-list of North American Birds(American Ornithologists' Union, 1957).It seems obvious that this fine volumewill continue to be useful.

Birds of Hawaii is a new printing ofa book first published in 1944; it hasbeen out of print for a long time and,consequently, was difficult and costly toobtain. When Hawaii became a state,it was felt that the occasion justifiedpublishing a revision of the onlymodern compendium and manual forstudying the bird life of the new state.The chief alterations in this printingare the addition of a handy list of allthe changes made since 1944 in theclassification and nomenclature of thebirds and the replacement of some ofthe less satisfactory illustrations foundin the original printing. If and when a

new edition is published, I hope it willhave better color plates. The ones inthe present volume are not good enoughfor a state bird book; the text is farbetter than the plates.

HERBERT FRIEDMANNU.S. National Museum,Smithsonian Institution

New BooksMathematics, Physical Sciences,

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Alluvial Prospecting and Mining. S. V.Griffith. Pergamon, New York, ed. 2,1960. 255 pp. Illus. $7.50.Annual Review of Nuclear Science. vol.

10. Emilio Segre, Ed. Annual Reviews,Palo Alto, Calif., 1960. 624 pp. Illus. $7.Contains 15 articles written by 22 con-

tributors, including articles by F. Reineson neutrino interactions, H. Bradner on

bubble chambers, J. G. Beckerley on

methods for subsurface prospecting, andR. C. Thompson and J. B. Storer and D.Grahn on vertebrate radiobiology.

Automation. Its impact on business andpeople. Walter Buckingham. Harper, NewYork, 1961. 206 pp. $4.50.

Axiomatics of Classical StatisticalMechanics. Rudolf Kurth. Pergamon, NewYork, 1960. 190 pp. Illus. $7.50.

Basic Mathematics of Science and En-gineering. Reuben E. Wood. Sigma Press,Washington, D.C., 1960. $2.50.

Cermets. J. R. Tinklepaugh and W. B.Crandall, Eds. Reinhold, New York;Chapman and Hall, London, 1960. 245pp. Illus. $9.50.24 FEBRUARY 1961

Combinatorial Analysis. vol. 10, Pro-ceedings of Symposia in Applied Mathe-matics. American Mathematics Soc. Prov-idence, R.I., 1960. 317 pp. Illus.

Comprehensive Analytical Chemistry.vol. lB, Classical Analysis.~Cecil L. Wil-son and David W. Wilson, Eds. Elsevier,Amsterdam, 1960 (order from Van Nos-trand, Princeton, N.J.). 900 pp. Illus. $30.

Contributions to the Theory of Nonlin-ear Oscillations. vol. 5. L. Cesari, J. La-Salle, and S. Lefschtez. Princeton Univ.Press, Princeton, N.J., 1960. 296 pp. $5.

Crystal Structures. vol. 5. Ralph W. G.Wyckoff. Interscience, New York, 1960(not folioed). Chapters 14 and 15 and the"Index to organic compounds."

Electromagnetic Fields and Waves. Rob-ert V. Langmuir. McGraw-Hill, NewYork, 1961. 236 pp. Illus. $9.75.

Electronics for Children. Gabriel Reu-ben. Sterling, New York, 1960. 88 pp.Illus. $2.50.

Elements de Physique Nucleaire. Dan-iel Blanc and Georges Ambrosino. Mas-son, Paris, 1960. 238 pp. Illus. NF. 30.

Fast Reactor Cross Sections. A studyleading to a 16 group set. S. Yiftah, D.Okrent, and P. A. Moldauer. Pergamon,New York, 1960. 135 pp. Illus. $5.

Foundations of Geometry. Euclideanand Bolyai-Lobachevskian geometry, pro-jective geometry. Karol Borsuk and Wan-da Szmielew. North-Holland, Amsterdam;Interscience, New York, 1960. 444 pp.$12.From Theory to Practice in Soil Me-

chanics. Selections from the writings ofKarl Terzaghi. L. Bjerrum, A. Casagrande,R. B. Peck, and A. W. Skempton. Wiley,New York, 1960. 433 pp. $12. Contains a

bibliography and "contributions on [Ter-zaghi's] life" by Bjerrum et al.

Fundamental Physics. Jay Orear. Wiley,New York, 1960. 1961. 395 pp. Illus.$6.75.Fundamentals of Aerodynamic Heat-

ing. Robert Wesley Truitt. Ronald, NewYork, 1960. 269 pp. Illus. $10. From thepreface: "This book is an introduction tothe subject . . . developing . . . the theo-retical background necessary to a funda-mental understanding of laminar and tur-bulent boundary layers and their relationto skin friction and heat transfer." Truittis professor' and head of the departmentof aeronautical engineering at VirginiaPolytechnic Institute.Handbook of Textile Testing and Quali-

ty Control. Elliot B. Grover and D. S.Hamby. Textile Book Publishers, Inter-science, New York, 1960. 620 pp. Illus.$17.50.How To Use Algebra in Everyday Life.

By the editors of the Sterling PublishingCo. Sterling, New York, 1960. 253 pp.Illus. $3.95.Hydrodynamics. A study in logic, fact

and similitude. Garrett Birkhoff. PrincetonUniv. Press, Princeton, N.J., rev. ed.,1960. 196 pp. Illus. $6.50.

Inorganic Chemistry. Jacob Kleinberg,William J. Argersinger, Jr., and ErnestGriswold. Heath, New York, 1960. 688pp. Illus. $10.75.

Inorganic Syntheses. vol. 6. Eugene G.Rochow, Ed. McGraw-Hill, New York,1960. 283 pp. $7.75.

An Introduction to Astronomy. RobertH. Baker. Van Nostrand, Princeton, N.J.,ed. 6, 1961. 372 pp. Illus. $5.50.

Introduction to Atomic and NuclearPhysics. Otto Oldenberg. McGraw-Hill,New York, ed. 3, 1961. 393 pp. Illus. $7.95.An Introduction to Celestial Mechanics.

Theodore E. Sterne. Interscience, NewYork, 1960. 217 pp. Illus. Cloth, $4.50;paper, $2.50.

Introduction to Ceramics. W. D. King-ery. Wiley, New York, 1960. 799 pp. -Illus.$15.

Introduction to Nuclear Science. AlvinGlassner. Van Nostrand, Princeton, N.J.,1960. 223 pp. Illus. $3.75.

Introduction to Quantum Mechanics.Robert H. Dicke and James P. Wittke.Addison-Wesley, Reading, Mass., 1960.380 pp. Illus. $8.75.Lead Isotopes in Geology. R. D. Rus-

sell and R. M. Farquhar. Interscience,New York, 1960. 251 pp. Illus. $9.

Lectures on Differential and IntegralEquations. Kosaku Yosida. Interscience,New York, 1960. 230 pp. $7. The Englishedition, prepared by Shigeharu Harada, isa translation of a volume originally pub-lished in the series "Iwanami Zensho."

Linear Systems Analysis. An introduc-tion to the analysis of discrete-parametertime-invariant linear systems. Paul E.Pfeiffer. McGraw-Hill, New York, 1961.555 pp. Illus. $12.50.Mechanical Waveguides. The propaga-

tion of acoustic and ultrasonic waves influids and solids with boundaries. MartinRedwood. Pergamon, New York, 1960.309 pp. Illus. $9.Modern Factor Analysis. Harry H.

Harman. Univ of Chicago Press, Chicago,Ill., 1960. 485 pp. Illus. $10.New Mathematics. A unified course for

secondary schools. vol. 2. K. S. Snell andJ. B. Morgan. Cambridge Univ. Press,New York, 1960. 320 pp. Illus. $2.25.

Organic Electronic Spectral Data. vol.1, 1946-1952. Mortimer J. Kamlet, Ed.vol. 2, 1953-1955. Herbert E. Ungnade,Ed. Interscience, New York, 1960. vol. 1,1222 pp., $25 (subscription price); $28.50.vol. 2, 929 pp., $17.50. (subscriptionprice); $15. From the preface material:"In order to be included, the data had tosatisfy the following minimum require-ments: The investigated compound mustbe sufficiently pure to give satisfactoryanalyses and definable by a molecularformula. The solvent or phase should bestated and the spectral data completeenough so that wavelengths of maximalabsorption and molar absorptivities couldbe computed even if they were not statedin the original publication. Later, it wasdecided to include data for which no sol-vent was given, provided spectral datawith solvents did not exist for such com-pounds." Volumes 3 and 4 are scheduledfor publication.

Oxosteroids. The use of phenolic hy-drazides for detection, characterisation, andestimation. Bernard Camber. Lewis, Lon-don, 1960. 79 pp. Illus. 12s. 6d.

Physical Methods of Organic Chem-istry. vol. 1, pt. 4 of Technique of Or-ganic Chemistry. Arnold Weissberger, Ed.Interscience, New York, ed. 3, 1960.1081 pp. Illus. $26.

575

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design of pattern-recognizing devices.One theoretical device is able to distin-guish patterns, regardless of their rota-tion or translation in the visual field, bydifferences in the frequency with whichthe lines of the pattern were inter-sected by a line segment, of fixed length,repeatedly placed in random orientationand position on the visual image (a"randomly tossed" curve).

Visual SystemsJ. R. Singer of the University of

California described a visual systemwhich, by means of radial scanning, canrecognize a two-dimensional object re-gardless of the visual angle it sub-tends or of its rotation in the visualfield. However, this system requires thatthe object be centered in the visual field,so it is unlikely that the visual systemsof living organisms, at least of verte-brates, use the same principle.A different type of artificial visual

system, designed by L. D. Harmon ofBell Telephone Laboratories, can recog-nize the convexity of a moving target.It consists of seven similar photocells,six tightly packed around the centralone. The output of the central photocellproduces inhibition at an artificialneuron; the output of the others, excita-tion. The neuron responds only to thepassage of targets with radii within a

particular size-range, according to thethreshold setting. This system may cor-respond to the convexity detectors inthe frog's eye, previously reported byLettvin, Maturana, McCulloch, andPitts.

E. E. Loebner demonstrated an arti-ficial visual system consisting of amatrix of photoconductors, each con-nected in series with an electric energysource and an electroluminor. Whenlight hits a photoconductor, this per-mits current to flow through the lumi-nor and causes the luminor to emitlight. By appropriate connections andinterconnections of these elements it ispossible to reproduce many of thefunctions of the vertebrate retina, in-cluding all four detection functionsfound in the frog retina by Lettvinet al. It is possible that some of thecircuits used in the model may be rec-ognized in the living retina.A machine capable of distinguishing

among the spoken names of the digits("one," "two," and so on) was describedby W. C. Dersch of International Busi-ness Machines Corporation. At leastone of the principles on which it oper-ates is known not to be used in thehuman auditory system. L. A. de Rosaof International Telephone and Tele-graph Corporation presented a theoryof the operation of the auditory system,

K= (A+B) C+A B

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The binary adder stage produced in conventional design above has been reduced andsimplified through Majority Logic design to the lower diagram and formula. Discoveredand formulated in the Remington Rand Univac Mathematics and Logic Research De-partment, Majority Decision Logic is a new logical algebra which opens new and inter-esting possibilities for the reduction in number of logical elements in computer design.

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explaining that its frequency discrimina-tion is produced by an autocorrelationprocess rather than by mechanical fil-ters. W. A. van Bergeijk of Bell Tele-phone Laboratories has built an artifi-cial neuron network which he considersanalogous to the spiral innervation ofthe cochlea and has measured signalloss as a function of simultaneous firingof several branches of the neuron. Nosimilar measurements have been madeon the actual nerve for comparison.He has also built an analog of abranching sensory nerve of the skin andhas found that the analog and suchnerves have comparable recruitmentfunctions.

Artificial NeuronsThe highlight of the symposium was

a group of talks by W. S. McCullochand other mathematicians from hislaboratory at the Massachusetts Instituteof Technology and by K. K. Maitra ofRCA Research Laboratories, on thegeneral problem, "How simple can aneuron be and still, by proper intercon-nection . . . perform all the knownfunctions of the brain?" They startedwith the very simple McCulloch-Pittneuron, which consists of a device thathas many inputs which can carry eitherexcitation or inhibition. It possesses apolar threshold such that the output isin one or the other of two states, de-pending ol whether the algebraic sumof the inputs does or does not exceedthe threshold value.M. Blum considered the general ques-

tion of what logical functions could beperformed by simple networks of suchneurons. He showed that if the numberof inputs (such as signals from differentsense organs) to a neural net is large,the number of logical functions whichthe net can perform approaches one-quarter of the totality of logical func-tions. This should certainly be enoughto perform the limited number of logi-cal functions which are known to becarried out by the brain.

A. N. Verbeek showed how toproduce reliable computation with a"noisy," unstable neuron having foursources of trouble: variations in thesignal strength of the inputs, faulty con-nections, variations in internal thresh-old, and inability to propagate its out-put signal. He used triplet networksmade up of three of the simple neurons,all the inputs to the triplet going inparallel to two of the neurons and theiroutputs going to the third neuron, whoseoutput was the output of the triplet.Signals from each input were connectedin parallel to each of many triplets.Each of these performs the logical oper-ation, and the output of all the tripletsgoes to a neuron which acts as a major-ity decider, taking the outputs, compar-ing them, and deciding which is correctaccording to the output signals of the

SCIENCE, VOL. 133

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majority. If each neuron is capable ofproducing an error 5 percent of thetime, the upper limit of the probableerror of such a net can be made lessthan one in 1 million by a combinationof just 30 such redundant triplets. Thiswork is of great significance, since upto now the only theoretical method ofincreasing reliability has been to putmany elements in parallel wherever oneelement has been used in the originalnet. Von Neumann has shown that toachieve a reliability of one error in amillion by this older method with neur-ons which produce an error 5 percentof the time would require a net ofabout 20,000 neurons.Cowan presented the mathematical

logic he has developed for dealing withthe behavior of nets of neurons carryingon logical computations in the presenceof noise. He was able to represent ageneral noisy computation scheme andto calculate the amount of signal thatcame through.

K. K. Maitra presented an extensionof the work of Verbeek in the designof nets which reliably perform logicaloperations even though the neurons andconnections of the net may be un-reliable. He developed a simplifiedmathematical symbolism for describingthe manipulations of each triplet net-work. He was able to show that wherea certain logical function is desiredfrom the triplet, this function can beachieved with the greatest reliability bymaking the triplet from a combinationof neurons each having a particular logi-cal function, determined by a processhe could specify. In a similar way hewas able to show that if triplets arecombined into triplet networks andthese in turn into larger triplets, andso on, a minimum probability of erroris found in networks made by three orfour orders of such tripletting. Wheninstead of tripletting the triplets heduplexed them, this gave increasing reli-ability with increasing order of duplex-ing up to any arbitrary level of relia-bility. Thus, it is possible in theory todesign networks with unreliable neuronswhich will give any desired reliability ofperformance.

In a delightful summarizing talk, H.von Foerster of the University of Illinoispointed out the importance of this workon reliability. It permits the achieve-ment of increased reliability in a systemnot by increasing the reliability of thecomponents and connections but, moreeconomically, by multiplexing unreliablecomponents.At the end of the symposium a final

question was presented to McCulloch.He was asked, in effect, whether thepeople working on information proces-sing would not some day, like the nu-clear physicists today, have cause toregret the social consequences of their

SCIENCE, VOL. 133

w

work. McCulloch replied that he wasconvinced that it was in man's natureto develop both the socially good andthe socially bad consequences of anyinvention. He fully expects that theworld will be booby-trapped by the useof these and other sciences, but it is hisfirm hope that by making available in-fornmation-handling devices of greatcapacity man will prevent the detona-tion of that booby trap through mis-informnation.

LEO E. LIPETZInstitute for Research in Vision,Olhio State University, Columbus

Forthcoming EventsM\larch

19-25. Ciar-ibbean Region, AmericanSoc. for HorticLIltuiral Science, 9th annual,Miami, Fla. (E. H. Casseres, Londres 40,Mexico 6, D.F., or W. H. Krome, Box596, Homestead. Fla.)

20-22. American Physical Soc., Mon-terey, Calif. (W. A. Nierenberg, Univ. ofCalifornia. Berkeley 4)

20-23. Instituite of Radio Engineers,1961 intern. convention, New York, N.Y.(E. K. Gannett, IRE, I E. 79 St., NewYork 2 1)

20-24. Amrc-ica.n SUrgical Assoc., BocaRaton, Fla. (W. A. Alteimeier, CincinnatiGeneral Hospital, Cincinnati 29. Ohio)

20-24. National Health Cotincil. foru7mand annual meeting. New York. N.Y.(NHC, 1790 Blroadwav. New Yorki 19)

20-24. Western Metal Cong. anid Ex-position, 2th, Los \ng,eles. Calif. (A. R.I'Lltnam, Amer-icani Soc. for Metals, MetalsIPark. Ohio)

2 1-23. American Meteorological Soc.,general meeting. Chicago. 111. (E. P'. MIc-Claim. Dept. of MNIeteorology, Unisv. ofChicago, Chicago 37)

21-23. American Phvsical Soc.. Divisionof HighI-lolynier- Phxsics, 21 st, Monterey,Calif. (D. W. McCall. Bell I'elephione ab-oratories. MU rray Hill, N.J.)

21-23. American Power Conf., 23rdailllnLal. Chicago. Ill. (W. C. Astley, Ihila-cielphia Electric Co., 900 Sansom St.,iPhiladelphia 5. Pal.)

21-24. American Assoc. of Anatomiiists,74th arnntul.-1 Chicago. 111. (O. 1P. Jones,Dept. of Anatomy, Univ. of BuIffalo, Buif-f'alo 14, N.Y.)

21 -0. American Clhemlical Soc., 139th,St. Louis, Mo. (A. T. Winstecad, ACS, 115516th St.. NW, Washington 6)

23-2-5. American Orthopsychiat ic As-soc., 38th annuLal, New York. N.Y. (M. F.I.anger, AOA, 1790 Broadway, New York19)

23-25. QUantUrm Electronics. 2nd intern.conf., Berkeley, Calif. (J. R. Singer, Dept.of Electrical Engineering, Univ. of Cali-fornia, Berkeley 4)

23-26. International Assoc. for DentalResearch, 39th annual1, Boston, Mass.(D. Burrill, IADR, 311 E. Chicago Ave.,Chicago 1)

24-29. National Science Teachers As-soc., Chicago, Ill. (R. H. Carleton, NSTA,1201 16th St., NW, Washington 6)26-29. American Assoc. of Dental

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City State I1- _ _ _ _ _ _ _ _ _ ___ l

594

Schools, annual, Boston, Mass. (R. H. Sul-lens, 840 N. Lake Shore Dr., Chicago 11,Ill.)

27-31. Temperature-Its Measurementand Control in Science and Industry, nati.symp., Columbus, Ohio. (C. M. Herzfeld,National Bureau of Standards, Washington25, D.C.)

30-1. Southern Soc. for Philosophy andPsychology, Atlanta, Ga. (D. R. Kenshalo,Dept. of Psychology, Florida State Univ.,Tallahassee)

April

3-6. Massachusetts Institute of Tech-nology, centennial celebration, Cambridge.(Office of Public Relations, M.I.T., Cam-bridge 39)

3-15. Medical Conference, 11th, Nassau,Bahamias. (Bahamas Conferences, P.O.Box 1454, Nassau)

4-6. Electromagnetics and Fluid Dy-namics of Gaseous Plasma, intern. symp.,New York, N.Y. (J. Fox, MicrowaveResearch Inst., Brooklyn 1. N.Y.)

4-7. Society of Automotive Engineers,natl. aeronaultic meeting. New York. N.Y.(E. W. Conlon and G. W. Periman, 485Lexington Ave., New York 17)

4-8. National Council of Teachers ofMathematics, 39th annual, Chicago, Ill.(F. A. Janacek, J. S. Morton High School.Cicero 50. 111.)

5-8. Water Relations of Plants, BritishEcological Soc., symp., London. (F. H.Whitehead, Botany Department, ImperialCollege, Prince Consort Road, London,S.W.7)

6-7. Council on Medical Television, an-nual, Bethesda, Md. (Institute for Ad-vancement of Medical Communication, 33E. 68 St., New York 21)

7-8. Eastern Psychological Association,Philadelphia. Pa. (C. H. Rush, P.O. Box252, Glenbrook, Conn.)

7-9. American Assoc. for Cancer Re-search, 52nd annual, Atlantic City, N.J.(H. J. Creech, Secretary-Treasurer, Inst.for Cancer Research, Fox Chase, Philadel-phia 11, Pa.)

7-9. Fleming's Lysozyme, 2nd intern.symp., Milian, Italy. (R. Ferrari, Organiz-ing Committee, Via Modica 6, Milan)

8-9. Histochemical Soc., 12th annual,Atlantic City, N.J. (H. W. Deane, AlbertEinstein College of Medicine, Bronx 61,N.Y.)

9-13. American Assoc. of Cereal Chem-ists, annual, Dallas, Tex. (J. W. Pence,Western Utilization Research & Develop-ment Division, 800 Buchanan St., Albany10. Calif.)

9-13. American Industrial Hygiene As-soc., Detroit, Mich. (W. S. Johnson, Bethle-hem Steel Co., Bethlehem. Pa.)

9-15. American Institute of Nutrition,Atlantic City, N.J. (A. E. Schaefer,ICNND, Bldg. 16A, National Institutes ofHealth, Bethesda 14, Md.)

10-14. American Soc. of Civil Engi-neers, Phoenix, Ariz. (W. H. Wisely, 33W. 39 St.. New York 18)

10-14. Detection and Use of Tritium inthe Physical and Biological Sciences, in-tern. symp., Vienna, Austria. (Office ofSpecial Projects, U.S. Atomic Energy Com-mission, Washington 25, D.C.)(See issue of 17 February for comprehzenusive list)

LettersDrug Industry and Government

With reference to your recent "Sci-ence in the news" article [Scienice 132.1536 (1960)] commenting about gov-

ernment intervention in the drug in-

dustry, could it be that the author dis-played just a little cynicism (which isperhaps too common these days) insaying: "There is the danger not ofcordiality between the regulators and

the regulated. which is useful, but ofthe regulators' coming to forget that,despite the room for a great deal ofuseful cooperation, the regulators andregulated do, or should, after all, rep-

resent opposing interests and opposingpoints of view"?

It does not seem to me that a reallyobjective observer could conclude thatthe interests of the Food and DrugAdministration and of the pharma-ceutical industry are opposed. Rather,our interests are really identical: toprovide the best medicine for those inneed of it, or, putting it another way,

to protect patients from bad medicine.If the views of the industry and the

government differ from time to time,I think such differences are largelyconfined to the question of how we

attain our common objective. This may

be a fine point, but it is one that is

useful in the interests of clarity.AUSTIN SMITH

Phlarmaceutical ManulfactuirersAssociation, Washington, D.C.

DNA's and RNA's

In the realm of biochemistry, names

(of substances) are used to designateproducts in which substantially all themolecules in a sample are the same, or

at least potentially the same, throughtautomerism. To speak of a mixture ofstructurally different molecules, as

though they were all the same, causes

misleading muddlement. The same

principle holds for alphabetical ab-breviations such as ATP, ADP, AMP,TPP, FAD, and TPN. For example,AMP stands for adenosine-5'-phosphate.If it were used indiscriminately to desig-nate the 5'- compound, the 3'- com-

pound, the 2'- compound, or the 2'.3'- phosphate, this could only cause

confusion.A widespread violation of this prin-

ciple, which can only result in confusedthinking, particularly on the part of un-

suspecting biology students, is the use

of the designations DNA and RNA as

though they, too, represent single spe-cies of molecules. This is particularlyobjectionable because there must be a

multitude of DNA's and RNA's and

SCIENCE, VOL. 133

EPIDEMIOLOGYOF MENTAL DISORDER

AAAS SymposiumVolume No. 60

Edited by Benjamin Pasamanick

A symposium organized by theAmerican Psychiatric Associa-tion to commemorate the centen-nial of the birth of Emil Kraepe-lin; cosponsored by the AmericanPublic Health Association.

. . . pioneering interdisciplinarystudies by investigators from bio-statistics, genetics, obstetrics, pe-

diatrics, psychiatry, psychology.public health and sociology.

December 1959, 306 pp., $6.50AAAS members' cash orders, $5.75

English Agents: Bailey Bros. & Swinfen, Ltd.West Central StreetLondon W.C.1, England

American Associationfor the Advancement of

Science1515 Massachusetts Ave., NW

Washington 5, D.C.

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their biological functioning dependsspecifically upon the existence of agreat diversity of molecules. To speakof a DNA or the DNA's is proper, butto refer simply to "DNA" as thoughit designated a chemical substance isunfortunate and leads to mixed-upthinking on the part of those who maynot be fully initiated.

ROGER J. WILLIAMSClayton Foundation BiochemicalInstitute, University of Texas, A ustin

Stimulus Generalization Gradients

In a recent report [Science 132, 1769(1960)] Eliot Hearst compares the stim-ulus generalization gradients obtainedin the case of each of a concurrent pairof responses, one response being main-tained by an appetitive reward, the oth-er by aversive reinforcement. From hisresults he concludes that aversive re-inforcement produces greater generali-zation (flatter gradient) than an appeti-tive reward. This conclusion is notwarranted from the data presented be-cause there is not even an attempt toequate the drive level corresponding tothe two responses.

Since the earliest Pavlovian work ithas been known that increased hunger(deprivation) flattens the generalizationgradient of an alimentary conditionedreflex. Hearst could have readily manip-ulated the flatness of his appetitive gra-dient in this fashion. In the case of theaversively maintained response, therelevant drive variables are the intensityof the electric shock, the number ofshocks received, and the time since thedelivery of the last shock. Of these, thefirst is particularly significant. By de-creasing the shock intensity in condi-tioning the avoidance response, a sharp-er gradient would have been obtained.The equating of drive between posi-

tively and aversively reinforced habitsis certainly unattainable in practice, andprobably even in principle. Thus,Hearst's conclusions would in any casebe questionable. The report would havehad some factual value, however, if thedeprivation schedule of the food-rein-forced response and the electric shockparameters had been clearly describedin the text. The absence of this informa-tion means that the data are not evenreproducible by the noninitiated reader.

MICHAEL F. HALASZDepartment of Psychology,University of Chicago,Chicago, Illinois

I am glad to have the opportunity tomake some additional comments on ourstimulus generalization data and to an-swer several points raised by MichaelHalasz.

1) Since appetitive and aversive24 FEBRUARY 1961

595

.': ;.:: .:. .:. i:X ::: '', .:i ::ax

drives have quite different properties,any attempt to equate them would bevery dubious. In my opinion this "ob-stacle" does not render futile or ques-tionable all comparisons of appetitiveand aversive behavior. A more positiveapproach to the problem might initiallyinvolve the design of a model situationin which both generalization gradientscan be obtained, and then an analysisof the effects of various factors on therelative slopes of the two gradients. Inour laboratories my co-workers and Iare currently investigating such vari-ables as type of avoidance and rewardschedule, kind of response measured,visual versus auditory cues, method oftesting, and amount of food depriva-tion to determine whether the reportedresults can be generalized to a widervariety of experimental conditions.

2) Extremely flat gradients of thesort reported for avoidance have rarely,if ever, been noted in prior investiga-tions of appetitive drives, even with ex-tremely high hunger motivation [for ex-ample, with subjects at 60 percent ofnormal body weight (1)]. In supportof our avoidance findings, Sidman (2)has recently presented data which alsoindicate a very flat gradient for the typeof avoidance behavior we studied; Sid-man's results were obtained for an au-ditory dimension, and the two subjects

were trained under different levels ofshock.

3) It is not likely that shock param-eters are extreniely influential variableshere. The monkey subjects rarely re-ceived more than one or two shocks per2-hour session, and such factors asshock level, number of shocks, and timesince preceding shock probably are im-portant only in a situation where ameaningful number of shocks are re-ceived. In any case, it was noted in thereport that no rewards or shocks werepossible during generalization testing.Thus these factors could not have had adirect effect during the generalizationtests sessions.

4) Halasz's assertion that decreasesin shock intensity would have resultedin sharper avoidance gradients is ratherpremature, since there are very fewexperimental data bearing on this prob-lem. As a matter of fact, Sidman (2)has recently shown that threefoldchanges in shock duration, though af-fecting response rate, have no effect ongeneralization. Additional experimentalwork is needed on this interesting prob-lem, however.

5) The specific parametric values ofthe reported experiment are typical ofthose used in many current comparativestudies of appetitive and aversive be-havior-for example, in several pro-

ductive investigations of differentialdrug effects on reward-motivated andfear-motivated behavior. Limitations ofspace made it impossible for me to in-clude several details of the experimentalmethod in the published report. Themonkeys were maintained during theexperiment on a daily diet of 60 to 70Foringer D & G whole diet pellets, andeach monkey was given one orange im-mediately after the session; the subjectshad thus been food-deprived for ap-proximately 22 hours at the beginningof each experimental session. Waterwas continuously available in theirhome cages. The shock level was set atan intensity of approximately 5 ma(0.6-sec duration), and shocks were de-livered through a Foringer shock powersupply and grid scrambler, which ran-domly reversed the polarity of the vol-tage on the grids. According to theanimal's particular posture and move-ments at the time of punishment, theshock might vary by as much as 0.5 to1.0 ma from the predetermined value.

ELIOT HEARSTCliiiical Neltropharmiacology Reseat-c/iCenter, Saint Elizabethi/s Hospital,Was/iinglton, D.C.

References

1. D. 1R. Thomas and R. A. King, J. Exptl.Ps. c1hXol. 57, 323 (1959).

2. M. Sidman, J. Exptil. A ial. Behavior, in press.

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