Kodak reports to laboratories on:processing your own 16mm film ... determining bovine pregnancy ... a fast blue-sensitive plate... a new method of supporting frozen tissue sections

16mmOne day in the early '20s a pair ofKodak research men reached theconclusion that sixteen millimeterswould be a reasonable film widthfor reversal-processed non-theatri-cal movies. Presently "16mm" hadimbedded itself into the technologyof our age, adaptable alike to pur-

poses of family sentiment, gaiety,art, instruction, promotion-anddata-recording. Perhaps you toowould like to use it for the latterapplication but have not realizedthat you don't have to wait for thepostman to deliver the results. Beinformed, then, that you can do re-

versal processing (and, of course,

negative processing) of black-and-white 16mm film in your own lab-oratory. You use Kodak Super-X,Plus-X, or Super-XX Blue BaseReversal Film, which, unlike theCine-Kodak Films, have no proc-essing charge included in the pur-chase price and no black anti-hala-tion backing to get rid of during theprocessing.

Information on processing Kodak BlueBase Reversal Films is available fromEastman Kodak Company, Sales Serv-ice Division, Rochester 4, N. Y.

To be reasonably sure

From Country Gentleman we haverecently learned that one of our

products is good for spotting preg-nant cows. You permit a urinesample from the bossy in questionto stand at room temperature, thenadd a saturated aqueous solution ofIndophenol Sodium Salt. If greenturns out to be the prevailing colornote, rejoicing is in order. Thismethod told the truth 91% of the

time in one herd of 136 cows. Allwe know about it is what we readin Country Gentleman (September'52, p. 57).Indophenol Sodium Salt is just one

of over 3500 Eastman Organic Chemi-cals. For a copy of our catalog, writeDistillation Products Indus-tries, Eastman Organic EDO,;Chemicals Department,Rochester 3, N. Y.

Fast, blue-sensitive plateIt might seem that a panchromaticphotographic material should bemore sensitive to tungsten light(3000 K) than a "color blind" onethat quits with the end of the bluethird of the spectrum. Not neces-sarily so. We make a plate of thelatter category that is as fast as our

famous Kodak Super Panchro PressPlate-as much as twice as fast forexposure times of the order of sev-eral hours. It's the Kodak Spectro-scopic Plate, Type 103-0, admiredby spectroscopists for its moderate,uniform sensitometric gradient allthe way from 2400A to 4400A.Manufacture of these plates hasbeen confined within the ivy-coveredwalls of our Emulsion ResearchLaboratory because the platesseemed to be of somewhat academicinterest. We couldn't have beenwronger. Lots and lots of peoplewant high white-light sensitivitywith the convenience of handlingby reasonable safelight illumination(Kodak Wratten Series 2) and don'tneed to preserve tonal relationshipsin flesh, foliage, and fabrics. Toserve them by immediate shipmentof a highly uniform product, we

have switched Type 103-0 to our

regular plate manufacturing depart-ment. (They have ivy on their wallstoo, but their machinery has more

capacity.)Kodak Spectroscopic Plates are sold

by the Kodak Industrial Dealer in yourarea. If he has not already been supply-ing them to you, your note to EastmanKodak Company, Industrial Photo-graphic Division, Rochester 4, N. Y.,will bring full information and get yourshipment moving to your dealer.

Frozen sectionHaving crowed at left about highphotographic sensitivity, we areequally pleased to announce KodakFrozen Section Stripping Film,which has no sensitivity whatso-ever. As diagrammed below, it con-sists of 10 microns of plain softgelatin on a 24-micron celluloseacetate film base atop a convention-ally thick film base that serves as astrippable carrier until the thickfilm is removed and the gelatin isstuck to a frozen tissue section inthe pathology laboratory. The thincellulose acetate provides supportfor the tissue during the slicingstroke of the microtome, so thatundistorted sections as little as 5

Specimen

Glebtin App' lo Film Bass App 24p^I

Film Be. Strippinc Point

microns thick may be obtained withno extraordinary manipulative skillfrom fragile tissues such as fattytumors, thyroid glands, and lymphnodes. If the gelatin is prestainedwith thionine or toluidine blue, thestain is transferred to the tissue sec-tion quite satisfactorily, giving a

finished slide from a CO,-frozenspecimen in about a minute. Pho-tography has nothing to do with allthis unless and until a photomicro-graph is required. This method isthe work of a very famous andversatile friend of ours, Dr. Van-nevar Bush, whom you hear aboutmuch more frequently as a researchadministrator, engineer, computingmachine pioneer, and philosopher.Kodak Froze,t Section Stripping Film

comes in uniperforated 35mm strips 25feet long. To fi,nd out about acquiring aroll, write Eastman Kodak Company,Industrial Photographic Division, Roch-ester 4, N. Y. The paper by Dr. Bushand Richard E. Hewitt, which gives de-tails of the method, appears in TheAmerican Journal of Pathology, 1952,XXVIII, No. 5, pp. 863-873. A

This is one of a series of reports on the many productsand services with which the Eastman Kodak Company and

its divisions are ... serving laboratories everywhere minumin

SCIENCE, Vol. 117

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A General Zoology of the InvertebratesThird Edition by G. S. CARTERThis new third edition of an introductory text for beginning students includesthe most recent zoological material plus revised and new drawings. The sectionsdealing with the biology of protoplasm and the cell and with the behavior ofinvertebrate animals have been completely rewritten. Price: $5.75

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SCIENCE, Vol. 11716

AN INTRODUCTION TO STATISTICSBy CHARLES E. CLARK, Emory University. Emphasizing statistical inference, this book pro-

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STOCHASTIC PROCESSESBy J. L. DOOB, University of Illinois. The author first provides a solid introduction to prob-

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Ny"Uev' mcGRAW-HIL lMooksCOMPLEX ANALYSIS

By LARS V. AHLFORS, Harvard University. International Series in Pure and Applied Mathe-matics. 247 pages, $5.00

A first-year graduate text covering the elements of the theory of functions of a complex variable,this text places emphasis on a true understanding of the whole structure of the material covered. Thereader who has mastered the book will comprehend the use of complex analysis in physics and relatedfields; he will also be well equipped for further study of complex function theory.

ADVANCED MATHEMATICS IN PHYSICS AND ENGINEERINGBy ARTHUR BRONWELL, Northwestern University. 476 pages, $6.00

Presents a mathematical foundation in the principal branches of advanced mathematics used in phys-ics and engineering. The fundamental laws of the more important areas are first expressed in verygeneral form. These then become the springboard for the development of vast areas of applications.The text shows how the fundamental formulations simplify to special cases which usually form thestarting point in solutions of problems.

LOGIC FOR MATHEMATICIANSBy J. BARKLEY ROSSER, Cornell University. International Series in Pure and Applied Mathe-matics. 530 pages, $10.00

A comprehensive treatment of symbolic logic, this book offers an exposition of those principles oflogic which are used by the mathematician in his daily work. The logic is developed simply at thestart from first principles. Then the formal concepts are related directly to the fundamentals of think-ing in all fields of mathematics up through the theory of cardinal and ordinal arithmetic.

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A text for a senior or graduate introductory course in mathematical analysis, this book is intendedprimarily for the mathematics major. It develops methods and theories of analysis on the frame-work of a number of physical and fundamental engineering problems. It includes such topics asinfinite series, continuity and compactness, the Reiman-Stieltjes integral, power series, Fourierseries, the Lebisgue theory, etc.

FLUID DYNAMICS. Fourth Symposium on Applied MathematicsM. H. MARTIN, Editor, University of Maryland. In press

This book consists of papers presented at the University of Maryland meeting in June 1951 of theAmerican Mathematical Society. Contributors include C. C. Lin, G. F. Carrier, A. Veinstein, S.Chandrasekhar, L. Onsager, G. Birkhoff, J. D. Synge and many others.

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Advances inCancer Research.

Edited by JESSE P. GREENSTEIN, National Cancer Institute, Bethesda, Maryland, andALEXANDER HADDOW, Royal Cancer Hospital, London

VOUME IMarch 1953, xii, 590 pages, illustrated, $12.00

T HIS new series is designed to present authoritative reviews by outstandinginternational experts on various phases and areas of cancer research.

Since cancer research is not a single subject, but a combination of a numberof separate disciplines, each volume of the Advances in Cancer Researchlwill include reviews on a number of different scientific approaches. It willnot be forgotten that cancer is a disease as well as an academic problem ingrowth, and it is anticipated that after the first volume each succeeding onewill contain at least one presentation of clinical research.

Contents:

Electronic Configuration and CarcinogenesisBy C. A. COULSON, King's College, London

Epidermal CarcinogenesisBy E. V. COWDRY, Washington University, SaintLouis, Missouri

The Milk Agent in the Origin of MammaryTumors in MiceBy L. DMOCHOWSKI, University of Leeds, Eng-land

Hormonal Aspects of Experimental Tumori-genesisBy W. U. GARDNER, Yale University School ofMedicine, New Haven, Connecticut

Properties of the Agent of Rous No. 1 Sar-comaBy R. J. C. HARRIS, Royal Cancer Hospital,London

Academic Press

Applications of Radioisotopes to Studies ofCarcinogenesis and Tumor MetabolismBy CHARLES HEIDELBERGER, University of Wis-consin, Madison

The Carcinogenic Aminoazo DyesBy JAMES A. MILLER and ELIZABETH C. MILLER,University of Wisconsin, Madison

The Chemistry of Cytotoxic AlkylatingAgentsBy W. C. J. Ross, Royal Cancer Hospital, Lon-don

Nutrition in Relation to CancerBy ALBERT TANNENBAUM and HERBERT SILVER-STONE, Michael Reese Hospital, Chicago, Illinois

Plasma Proteins in CancerBy RICHARD J. WINZLER, University of IllinoisC6llege of Medicine, Chicago

Author Index-Subject Index.

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What GENERAL ELECTRIC People Are SayingS. P. _NrEWBERRYGeneral Engineering LaboratoryIn the early excitement of the electron micro-scope, research workers joined in a mad rushto obtain higher and higher magnificationpicttires. Nearly five vears elapsed before itbeciame generallv reco'gnized that magnifica-tions of 10 to 100 thousand times were far toogreat to correlate results with previous magni-fications, usuallv less than one thousand times.A practical idea of the difference in magni-

fication can be gained by considering the 1 -

inch. 200-mesh specimen grid of the electronmicroscope. At 1000 times magnification itsimage is 10 feet across, and a single mesh open-ing is approximately 2" square. Now at 100tlhouisand times magnification the screen ismore than Y1-mile across and the individualmeslh opening is over 17 feet. An 8" x 10" pic-ture obtained at 100 thousand times representsa sampling of only- .2%, of the area of a meshopening and onlv 2/100,000%o of the tiny 18'specimen we started out to explore. Experi-ence has taught us that we must increasemagnification in gradual steps of about 3Xper step if we are to form a definite conclusionof how the minuite structures are correlatedwith the over-all struetuire. Indeed, when wechange methods of viewing or methods ofspecunen preparation, it is often necessary tocompare pictures at the same magnification,actually superimposing i(lentical fields of view,so we may maintain continuity With pastknowledge.

After finding out that the highest magnifica-tion is not alwavs the best, the electronmicroscopist has another important lesson tolearn. lie must realize that he cannot live inan "ivory tower," solving problems by crystalgazing in his microscope. Ile must work withthe people who have the problems in the shop.He must help them to choose and preparesamples, and thev must help him interpretwhat he photographs. He should encouragethe use of other equipment to support orcheck his own findings. The electron micro-scope adds the very important element ofvision to problems which depend upon theultrafine structure of matter, but it does notgive all the answers by itself.

7th National I.S.A. MeetingCleveland, Ohio

E. S. LEEPublic Relations DivisionRECOGNIZE THE ENGINEER: In engineering, theproduct's the thing. It is the product aroundwhich evervthing moves and toward whiclhevervthing is directed. The scientist bringsforth new knowledge from nature; the engineerforms that knowledge into products for peopleto have and to use. The engineer may improvepresent products or create new ones. Butthroughout, the product's the thing.

This is what makes engineering universal;this is whv engineers are in the forefront ofevery advance.The engineer has been so busv doing things

that he has not brouight hlis storv to the peopleof our countrv. Therefore they do not recognizethe importance of his story, and thus far hisrecognition has been a problem for him alone.Buit today the seriousness of our worl(d situa-tion has taken the problem out of his hands.It is now a problem for the nation-engineersmust be conserved for engineering, and theirnumbers must be increased.

This demands an earlier nlnderstanding ofthe engineer by the public at large. It demandsthat he receive the recognition due him in sub-stantial degree. It demands that militaryassignments be made onlv for necessity intechnical matters. It demands that secondarvschool curriculums be complete with the neces-sary phlysics and chemistry and mathematicsto provide the best training for those enteringengineering schools. And it demands that thoseyoung people capable of advancing in engi-neering be eager to tackle the hard work whichthe training requires.There is an imperative need for this under-

standing if our nation is to advance its presentworld position. The creative ability of theengineer is meeting its greatest challenge. Butnow the engineer must create another newproduct: a universal and spontaneous recogni-tion of the engineering profession.

General Flectric Review

G/oaE ~N uERAL a~E4dILcECoI

GENERAL*EELECTRIC

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for ordinary microscopes

with MOPhase Microscopes

Living organisms and tissues, pale or faded preparations,emulsions, plastics, and other materials are often too

transparent to be seen by ordinary bright field micro-scopy.

Phase microscopy converts invisible differences in densityin the specimen into images which are clearly seen andphotographed.

AO pioneered today's methods of phase microscopy bydeveloping numerous gradations and types of contrast

for emphasizing different details and insuring thatnothing is missed in examining transparent specimens.

Whether you prefer a standard contrast outfit whichsuffices for most applications, a small, special purpose

outfit, or the most elaborate equipment AO's longexperience and complete selection of equipment are your

best guarantee of satisfaction. For literature, writeDept. Qi.

American OpticalW INSTRUMENT DIVISION

BUFFALO 15. NEW YORK

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