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whom I felt would "stay with it "longest.In this situation the lonig-term value ofthe commodity determines its price, notthe immediate value. Lab directors justdon't want and won't pay the sameprices for people whom they suspecthave a high chance of leaving.

I tried this letter out on a femalecolleague. On the dead-run out of herlab and over the crash of flying Erlen-meyers I caught her riposte: "You ham-merhead, the lower survival rate is theresult of the dollar discrimination!"

DEMOREST DAVENPORTDepartncmnt of Zoology,Untiversity of Californtia,SaItEt Bar-bar-a 93106

those who have written so vehement-ly about disparity between pay for menand women employees (particularly sci-entists) have not considered the employ-er's side of the coin. In buying the serv-ices of any equipment, mechanical, ani-mal, human, or otherwise, the purchasermust consider return on his investmentrelative to initial cost, upkeep, depreci-ation, and perhaps other factors withwhich cost accountants are most famil-iar.When hiring a scientist, male or fe-

male, the employer must look to the fu-ture. What is the productive life expec-tancy of the individual? What is theprobable productivity of that person interms of what the employer wants? Howmuch will the individual cost per unitof output? And, could some other pro-curable person give comparable or moresatisfactory service at the same or acheaper per-unit cost? In view of theapprenticeship required for maximumproductivity on most jobs, probable ab-senteeism, retirement and disabilitybenefit costs, and so forth, these arevalid considerations. Some years ago Ifound that some employers would notconsider "common labor" beyond age40. Their reason: It costs too much forretirement benefits for the time aheadthat they can do this type of work.

I have seen no data comparing therelative per-life-unit-output cost of menand women in science, nor in any otheroccupation. I have heard that (i) mostyoung women work only until they canfind husbands; (ii) most mothers are en-grossed with their families and not withtheir jobs; (iii) women are of uncertaintenure because their husbands move;(iv) pregnancy and parturition decreasethe working woman's usefulness on thejob; (v) women are not as dedicated togetting ahead as men are and, conse-quently, are not worth as much; and

(vi) women cause more friction andconflict than men.

During the past few years I havebeen instrumental in hiring several psy-chologists-men and women. My frus-trating experience is that women andneophyte male psychologists are riotgood risks for employment in a com-mLlnity mental health program outsidea large city. They don't stay long enouLghto become effective. They're looking for"a place to jump"-one with more "so-cial advantages" and opportunity tostart at the top of their profession.

I suggest that scientists come up withbetter predictive measures of lifetitmeprofessional output-also with short-term expectancies-before they becomnetoo exercised at what they cannot proveto be discrimination. What we see asdiscrimination may in fact prove eco-nomically and socially justifiable. Thereis no virtue in preferential treatmentof a minority because it is a minorityanid may have been discriminatedagainst.

MILTON B. JENSEN1405 Jacobsoni Circle,Situ. City Ceniter, Florida 33570

DDT Proponents Challenged

The counterattack by pesticide manu-

facturers and their associates in defenseof DDT charges environmentalists withbeing "emotional" and "hysterical" intheir efforts to curtail the use of DDT(Letters, 27 Nov.). Lykken, formerlywith Shell Chemical Company, speaksof "the emotional oratory about theapparent decline of certain species ofbirds...." Nevertheless, the literaturereveals abundant documentation bycompetent scientists on the inhibitionof avian reproduction by DDT, themechaniisms involved, and their delete-rious impact on populations of carniv-orous birds (1). Unsupported chargesthat this work is "emotional oratory"are themselves indications of irration-ality, yet they continue to appear inthe popular media and as letters toeditors of journals. If Lykken or hiscolleagues have any evidence 1fromscientific studies showing that DDT hasn1ot catused the declines of these birds,they have certainly kept it a closelyguarded secret. Until they publish suchevidence in the scientific literature.most scientists will continue to believethe numerous refereed research studiesthey have already seen, rather than un-stupported rhetoric.

SCIENCE, VOL. 171

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\'hite-Stevcrs. fornmerlyrs ith Amicricaln (Uvananid. thrcaltens that Ws1ithont[)DI- and the like thcre%, ill he dliscls..losses of food crops. aticddcv astat ionof for1 ests i-oma vast hordics o tlics.fleas, iiioscllttoes. cockriolches. tcr-liItes, aIl ii v\ ad.l other Lin no inchonsehold Mnd ho g1a.oardenle iliscts.\Aailn, tfihs an,d 1i,1iv siimlar s\wecping statmeniets his a lew highls \ocalDl) I proponents are cnti,relN LinIsuLp-po-t ed. Ho., did WC snir\ ise hItore-.1 94'' 1The insie_lnificance of DD-I infood 1t odIttcthon is deCiiosttiateed hVr ItsLSce on lCss than,] I pe-rCltcctiio the foodcrOP etecet1c ill thec Uniteci Statesand its neatr Isv complll Iete cliniiInatio)n]ft olni LISC iil ( ailt-taorra. onr1- ichlest andmost ;nii olitie bfoo prodnetritcil state.

\ olonl non()ls doennientsatil iona lndicAtelthat crop vic1cls are malntlaind aridoticln netvealsed, lnot decreaIsed. hs iii-terl'tItcl colntl't l pi'0 t a,1lls thltlt VIse lCsSir1"ctisittce arid no DDI (3). It is It

11rIttcr ot r1cord1 that rIo inisect lestprohllleil has liecni Clilililla,tc.t is ii-zseticiclcs. ltci. in f aett thlait milaris hasvebcen ((iiic1d is these chcilc,ds- istile tatXOCt peSt rCscti etCleCCS SCCOI1Cla1rpiest octthrelaks, arid pcst iesistanice thaltfoll0\5 the ctisselmiitntioll cto lhroald spec-it crtii iciscits

It is CLII-iocIs that 11)1 prolcipdtishas iciot as ailed themselsvcs c th-riotiil a1 chaltis tfl- ptlichlhI ttciii c t

seteitcIlti nfcll nllaltnll, ss hile cei'dencecaItlist 1)D cc)iit'lInLIs to iC pcthlishrScd

ill tle sceintitfic litelac altilcist w-eck-v. cicrthelcss, thle nliliher- citPltp--1L) I ICttCl-s snI(T,,Csts that there idiListlIC orutCI/Iiiti, to sLIpport thcrii. Sinlvcethe I-Awlis t cir ilttal Deftensc FLIndicl arid

othe- organlizations hasVC LI1ndclrtakciIittigtItorll i aailist DDTI ill sesc ral led-eral Cocirts. I)DT proponelits wsill hasveam11plC ocppoItLiIitf to hasVC their- e i

deice helard in MIan irap til f irL1i11shierc its validitv can he tested tiycrciss-cxaniliatilon. It irS LIifot0IntLtCthlat the DD'F propoiicnts swho speakso tf reqclCiitsiiV the ieclia hsvc so faras oirled ans ole iin this litigatioi . thLIsmallit.iillirlCv seCrcsC aticiicld the cvi-dieiuce tcil- thirli posititoll.

CIt\smu s F. \VWLRS tJl-RRY L. Nlossi Vt

MAlit;llic(' .Sciencit 1, R(' 1'(i'c/h C cit/cr.Stalc( nhclvcn-itx of Ncnw York,.S/torx Brook /1790i

FIDWIN H. Bst--i-uFYAirrr reti D. C ARI SON

JOHN Nt Fm itN1Rornr RI- F. SMOt KI VR

Di vision o/l Bioo,i/ic(l/ .SS'cic'cts('.,S/ttc I niivcr1it/v of \ crr }l'ork

Retereiice s

Bi. Pl',1ikrii Siric .( 168. 592 (197i): Sit,. 222. 72 197(t S N . 55 clov. m Vt

w'',t. \ut,.,i 227. (1'9()): R C. lIcrir..)55 11 .1 Kr,.ii i/ri'd. 224, 4-

II 90() Vt- r nr.rd 5 N 5 irPSc itic 165. 1 9 69 ItiKc Jil 1)5 Solvetlsol. i/id, 162 ' s).

I I p /l-.ic1/1 5 t*9 ,).R. Siiritli rind I 1i1 dtvi 13.'B . i ,,II I'

( VV/,i\- 5\ ki ")Irc' r Idt R I ID)tit I-dI(S rdcriirv 'ii.'§)'. Nyu 'i\ irok ti)(-i: Vt, ur;1c nt1 ic it (al.. in Bi(rrir",ii (C rntrii()I. BI

F111A CIt', EC1. PICltsI-1111 P)!t'i- N\%"\ )l t . iII

pi Vts>,: R. v'm dciin i irh . / ,11it i,nlcll 12. 'I

I .vkkc states: -I envc otic accclptst}.le illotiolil cirltoivS hliit t tle .cuir cIccltie c)t cer tainr sp cirs ol [iidlsridlfish alrd ath(oclt the lie1seC1tie ol121)D'I tCsiclICs ill 1iictieC-s' iiilk. ttheaict Cmiainis thaIt tli icr is liot oll\ es-

dchriee. elcoitciiial oit lrict (lia iii

11111 (//i(! /li Ill c/1I1 /1i/iII)i/I rt.dliesadded 1 rcimii thic legit rlmate *9crs t 1D1)arid othier pct sistcrt clilorii.iltcd iisecti-dCICs desllte W ichSpt-elac. hici_clc-VOLileC

cIsectC oserOV 0 ser.

I1clhidll.rtio(l decline s (t lieItIOs1 Ii

pclt.rlllria1(i the ricritre1iIlct ll 11twsell tchocticcrciitecl Hatchiili taMilIrIC chLIctco ttiill c-'shIlls assciclatcd w5ithi 1)1)

I-C'cidLels in the plai'cmt birds is also \\clcolcitctiitccl. It is irtresponisi ble tci iriiplsthat thleCse findings are11Ci11115 Cellc)tioirialalh(llc -1-Itie ital rc iizec stIatltcitent c-c-v.e,l1s an] aItr ci(ylct c thal.t I dci riot shia C.C'ill a111vll\ci decide swhich ariiiialAS areLsICt cr1l arid whlich a.1-C liot'.)

It is titic that DDl)F scrlstitLitCs thlalt.,,-. chclpl arid r-eachlils asarlble .Ire lia-rdto tillnch. I ohtsclcs ict 1rlcani that lioci-per sistenit. Sate.i ote select ise 1maltcrialsare icit kilos\il. We liasl severAl pcst-cidChs thlalt ate richICi 1riio-C to'ic tci in-sccts Inch svet at-c rlcnIIPe-sisteCit aindslafe to ise. Nciln is as chlleap ats 1D)1)1aIric t1lcost ar-c ncot recltils asilvable. bcrtthrss idciOLtI f;cilt It1-drs it ing so ciii toscirk ci the problemli.

D)D1I1 is riclo cielr cisech bs the U.S.Fol-est Scr s ice to eoimritit clf oilatill c

insects arid ttlier is1ric elecl oi ctirt toreirist,ite it that I aIm awssarc ot. \\ e

hal"\ riicire ethCctisVe a1id sat'el sLihstitLrtes One ol these is Z/ctr an. liesitets ct tlis Cchli IIcll tO biridS. Hilal.i-11.als. ardfis;h thas beeCn intenisisvelsStcIdiCdcl. It is iiLtnCi cII0rC tO\iC thlalnlD)D) l to C\srs insect species "se hLiaete>sted tle a licLiint neCeCd tIcirc-liitr cicit thie sprLlCe [Uidc0lsdril fol- CesaIi11iC.is o0ls 0. 5 1olcnlicl ((iS grat-IS) per' aICreCC0imparlChd tO pcOLIIICl cit DDT. Otlieriaiterals thiart s e are ss ckIIking witliiire ecsri iioti-C to\ic to clestr-nLctiseC iil-sects titclitll neot h.iz.iclciOiLs toi nonitargctaiiIiilMIs. hilt thcs aire itvesct r egistcrecd(1' r1s ltIhic,

Circle No. 80 on Readers' Service Ccird S( 11 -N( E, V()l I -I

If Sweden has had to resort to DDTto control destructive forest insects, Isuspect they are not actively workingon substitute materials.

DONALD C. SCHMIEGEInsecticide Evaluation Project, USDAForest Service, Post Office Box 245,Berkeley, California 94701

. . . Predator insects in a normal bioticsituation, or in one unaltered to anygreat extent by man, are animals use-ful to man and these are known tohave been destroyed by DDT and otherpersistent chlorinated pesticides....Some animals regarded as useful to

man have, in certain areas, lost theirusefulness. One example is the cohosalmon of Lake Michigan: in a shortperiod during the spring of 1969 theFDA seized 35,000 pounds of thesefish because they were found to con-tain levels of DDT dangerous to man(Science, 23 May 1969, p. 936). Asimilar situation occurred about a yearago with mackerel caught off Califor-nia. What is most shocking is that be-cause of the persistence and relativeinsolubility of DDT it will continueto build up in the oceans for the nextdecade or so even if its use werestopped today.

RiCHAiD K. HOSE10335 Stonydale Drive,Cupertino, California 95014

Psychologists' Preprint Plans

Constance Holden (25 Dec., p. 1385)reports statements attributed to DavidGrant, editor of the Journal of Experi-mental Psychology, as follows: "Grant. . . says that the APA journal, theAmerican Psychologist, accords virtu-ally no space to those who wish tocriticize NISP or offer alternative waysof improving the information system."

This is not the case. The AP hasnever refused to publish critical articleson the NISP program. I assume thatGrant was referring to the only twomanuscripts received in this office onthis subject. In one case the manuscriptwas withdrawn by the author almostimmediately after the manuscript wassubmitted; and in the other case, dur-ing the course of correspondence withthe author, he advised me that the arti-cle would appear as an editorial in an-other journal and was not suitable forpublication as a paper.

It would have been so easy for12 FEBRUARY 1971

Miss Holden to check the facts with theeditor of the American Psychologistbefore her article was published.

CHARLES S. GERSONIAmerican Psychologist, AmericanPsychological Association, 1200 17thStreet, NW, Washington, D.C. 20036

Constance Holden has made an hon-est attempt to capture the essence ofAPA's program for a National Infor-mation System for Psychology (NISP),and the opposition to it by some mem-bers of the association.... Her errors offact are relatively minor; for example,APA has never contemplated "com-puterized distribution of tape cassettesand films." Dean Kenneth E. Clark(University of Rochester, College ofArts and Sciences), chairman of APA'scommunications committee, can pro-vide accurate factual material on whichthe reader can make his own evaluationof the program.More distressing in her report is the

dearth of positive suggestions for theimprovement of the APA communica-tions program. The program's critics,first Jane Loevinger (Science, 27 Feb.1970, p. 1228), and now DavidGrant, seem-at least as reported-tobe avoiding substantive discussion. Bothdisplay a surprising lack of knowledgeof the way in which their associationfunctions. Projects are not designed andput into action at the whim and fancyof staff members in any of APA's pro-grams. In the communications program,for example, a ten-member governingcommittee duly elected by the councilof representatives of the associationreviews, criticizes, frequently initiates,and always authorizes the implementa-tion of a project. It then continuouslymonitors and evaluates such projects.When major policy is involved, theissue goes to the board of directors forits decision, and all other major APAboards and committees are kept in-formed by briefings at their scheduledmeetings.

Suggestions of dark and sinister plots(the machinations of "cabals," accord-ing to Loevinger) make titillating read-ing, as do denunciations of unspecified"half-witted schemes." As with most adhominem arguments, however, neitheris particularly useful in solving themanifold and important problems ofscientific information exchange in psy-chology.

KENNETH B. CLARKAmerican Psychological Association,Washington, D.C. 20036

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JUST PUBLISHED...

INTERMEDIATE ALGEBRA: Structure and Use

Raymond A. Barnett, Merritt College. 416pages, $9.95, January 1971.

Integrates and extends the essentials of a

modern elementary course in the first sixchapters. Intermediate courses with differingemphasis can be achieved by combining thesefirst six chapters with portions of the lastfour which are independent of one another.Sets, real numbers, and functions-and math-ematical structure-postulational approachand field properties, are emphasized.

TECHNIQUES IN PARTIALDIFFERENTIAL EQUATIONS

Clive R. Chester, Polytechnic Institute ofBrooklyn. 464 pages, $14.95, January 1971.

The presentation is based on geometricaland/or physical ideas. It is not a theorem-proof book, and pedagogical methods takeprecedence. For the applied scientist there isconsiderable emphasis on motivation.

ALGEBRA AND TRIGONOMETRY

Gordon Fuller, Texas Technological College.560 pages, $10.50, January 1971.

The concept of a set and the axioms of a

field are introduced early. The simplicity andclarity of the author's writing, emphasis on

analytic trigonometry with attention to com-

putational trigonometry, and effective use ofcolor to aid understanding are important fea-tu res.

PRECALCULUS MATHEMATICS

Kenneth Henderson, University of Illinois,Zalman Usiskin, The University of Chicago,and Wilson Zaring, University of Illinois. 480pages (tent.), $10.00 (tent.), January 1971.

The first part of the text reviews material thestudent has previously covered from ap-proaches designed for best calculus prepara-

tion. Careful exposition and a wide varietyof problems provide the reader with under-standing and skill in employing operationsand manipulating symbols.

McGraw-Hill Book Company330 West 42nd Street New York, New York 10036

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nooti1c ciltomioloov directly to pulblicheallth entomolon. Insect pi-tholooiststhILIs e-Cqiire guiidaInce froo 1lLi blic hc.lthi t(Iilltolists withl i-CSlpect to) coillitioils

oft vcior SiLarep-CSsioit nlcCenS;a-V to inl-terruPt the transmission o1 v'¼ OrLIS dinS-ealses.

It VV0s Lunini ntoi. siL agreed tl ilt

doimt the development ol pra;lctic.l1icrobl, .11 and intecrated techiiquLes of

VCctOi CoIltlrOl xxC i LiSt CoiltiinLie t10 de-

pe ndtL heaxV uIpO In C are-Cf 111 uISecd J eC'sti

cidc,, No0t¼¼ ithstandince this. iit w¼71n

POiiited out that at least some .dltern,-1ti\ to chemical conitrol .ire .alrlcod Oil

1 Id--ill pa tiN cuLbIt theC useC Ol lkt V i

j iis lish in ecolog-ica lly accecp-ta1bl1e %\' s

and old-I ishioned-' smnitatioital i lcthl-Ods. L oitil ste have cflcctixeitcicrohli.lp1o1c(dui-Ires and othler essenti,illxvnovel

control techlin iqle.S. Ct\ el\ '0eort lkib llit idC to S th .it t'Lill adCxV Is

takeni ol' tselis iitc dicatei v av .tl llS enIC ts dI ilh Iet ni lixt to che nti-

ic.i.tl p)esticides. iII the initetlest of 11o -

tIlt] pOs itiI veltosvtowrd mnethodolooies

sionl .ilLi initerruLI tiion ol vector-bornle

dise.i trilsmimssjiol \¼ ith the le.c it 115s-

i5ble it irm to the cl\ iilt il it.

I) /fcpartmTut eof IB ?io/ttv't. \J1ftetrialI 11 tcl/sint of \l ciolo tcdlailot

Ei l' t. ctt.c fouii l/o (Cainad/ia

Notelis

l \t it IS l t - t' 't '

f;I-th iop di (4 llhlic 11t ft11 t1-

11'It 0.l 0 od i it]'m' Ff tt

iif .1l5l f51 tti^ ;il ilt ihfifi\fllIl ;l i it.tiI! fts tftl il i S im pi f1ift[t' 1i 1f tT0 11'1l!v11.lt Mb'KI(ill I()ll ), 0 (1, t.lllll' 1 5-^(

t !; :ll; \| uli Il if;X fffiiffi li u. t'8\1'-~~~~ ~~~~c1I\IiS.INt) .

ft .I tt t t

For-thlcoiniig Lveents

\tlarch

/8 Polltitioni Control \tpositill and

Colnl 1s.. \AztlCs. ( ;lfit (G. 1). (Clottou.oi%:. ()I \M tnl aIti; ti in I' n iltc irs. 21050)FI-d kit.. Dcii-hornii. \tich. 4-81 28)

/ /7. ( il itlornia Nledical \ssoc .Ana-et1 .Rt I- otA ,t( 0\. 'S0 tttiet

F .fil cf.ct ( flIt! 1)41

/4 . iticnotien ;olm cAestheI.sia Re-

S('11 >N('[', ' 1711

P I T T S B U R G H * L O N D O N * F R A N K F U R T

H')5 Circle No. 86 oni Renccders Service Card

I k-(