SCIENCE---DDNEW SERIES SUBSCRIPTION, $6.00VOL. 93, No. 2425 FRIDAY, JuNE 20, 1941 SINGLE COPIES, .15

Measurement for Keen VisionYou open your eyes and you see. You are-

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2SCIENCE-ADVERTISEMENTS VOL. 93, No. 2425

BECKMAN pH NEWSFROM THE WORLD'S LARGEST MANUFACTURER OF GLASS ELECTRODE pH EQUIPMENT

Beckman Fiber Type CalomelElectrodes. Note one piece body andsmooth easy-to-clean surfaces. (Above)No. 270 Fiber Type Electrode. (Left)No. 1170 Fiber Type Electrode.

FIBER INSERT ON BECKMAN CALOMELELECTRODE SIMPLIFIES OPERATIONOne-Piece Construction Easier to Clean

In line with the Beckman policy ofconstant research and improvement,some time ago a new type fiber insertCalomel Elect-ode was introduced on

Beckmamn pH Equipment. Reportsfrom the field indicate that this newelectrode has pr oved very popular on

all types of pH applications.

Instead of the former. two-piece con-

struction, in which electrical junc-tion with the test, solution was madethrough a ground glass sleeve, thenew electrode features a porous fiberinsert sealed into the glass wall ofthe electrode. This advancementmakes possible a numbei of import-ant advantages. By eliminating theglass sleeve, the elect-ode is now onepiece, and therefore is unusually easy

to keep clean. Moreover, because ofits compact construction and smoothsuiface it can be more easily insertedinto semi-solids such as cheeses,moist earths, pastes, etc.

This fiber-type elects-ode is standas-dequipment on all new Beckman in-struments and can also be suppliedseparately to replace the glass sleeveCalomel electrode used on earlierBeckman instruments. Complete in-formation on this fiber-type electrodewill gladly be supplied on request.

National Technical Laboratories820 Mission St., So. Pasadena, Callf.

Commercial Fertilizers;Their Sources and Use

3rd EditionBy Gilbeart H. Collings, Ph.D.Clemson Agricultural College

Thoroughly revised, this book presents a prac-tical, up to date study of commercial fertilizers,their sources and use. It is based on the au-thor 's many years of experience as an experi-ment station agronomist and teacher of soils,fertilizer and crop courses. The conclusions of.auitlhorities within the fertilizer industry and ofexperienced agronomists are incorporated.131 Illustrations. 12 in Colors. Probable Price $4.50

Ready This Summer

Commercial Flower Forcing3rd Edition

By Alex Laurie, M.A., and C. H. Poesch, M.S.Ohio State University

The new edition of this widely used text pre-sents the fundamentals of growing flower cropsfor commercial purposes. It includes a com-plete rewriting of the section on soilless cuil-ture. Details regarding soils, fertilizers andculture( have been brought up to date. Themethods recommended follow the routine prac-tice of the better growers.

49 Illustrations. 565 Pages. Probable Price $4.50Ready This Summer

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2 SCIENCE-ADVERTISEMENTS VOL. 93, No. 2425

SCIENCE-ADVERTISEMENTS 3

HOMOCYSTINEand

HOMOCYSTEINETDIOLOGICAL INVESTIGATIONS conducted since theDJ.) discovery of homocystine and homocysteine sug-gest their importance in the metabolism of methionineand the relation of choline to that process.",2

Homocystine and homocysteine are similar in certainrespects, both chemically and biologically, to cystineand cysteine.3'4 Although never isolated from naturalsources, the biological importance of these syntheticsubstances has been established.

Increasing interest in these two compounds andinvestigations now in progress may disclose otherimportant functions for these synthetic sulfur con-taining amino acids.

Homocystine SMACO and Homocysteine SMACO,suitably purified for use in biological research arenow being prepared in the Research Laboratories ofS.M. A. Corporation.

1. DU VIGNEAUD, V., DYER, H. M., and HARMON, J.: J. Biol. Chem.,101:719:1933.

2. DU VIGNEAUD, V., CHANDLER, J. P., MOYER, A. W., and KEPPEL, D. M.:I. Biol. Chem., 131:57:1939.

3. SINGAL, S. A., and ECKSTEIN, H. C.: Proc. Soc. Exper. Biol. & Med.,HOMOCYSTINE SMACO 41:512:1939.in 1, 5 and 10-gram bottles. 4. VIRTUE, R. W., and DOSTER-VIRTUE, M. E.: J. Biol. Chem., 128:665:1939.

HOMOCYSTEINE SMACOin 1, 5 and 10-gram vacuumsealed ampuls. RESEARCH LABORATORIES

0 S. M. A. CorporationPRICES ON REQUEST CHAGRIN FALLS, OHIO

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JuwNE 20, 1941

SCIENCE-ADVERTISEMENTS VOL. 93, No. 2425

Constant

t mperature uniformityfor safe

incubation

The Castle Precision Incubator operates with a constancy of+ 1/0 C. and a uniformity of ±7/80 C., under full load conditions,

far In excess of the recommended tolerance of + 10 C., recommended

by the American Public Health Association.Less variation throughout the chamber Is shown by the Castle

because heat Is transmitted by Interior radiation, rather than byconvection. One thermometer will suffice for accurate temperature

measurementsThousands of calories of reserve heat, provided by twenty-two

gallon of warm water, accurately controlled, compensate quicklyfor any heat loss caused by opening of door. Changes In roomtemperature, if below operating range, do not affect temperatures'inside incubator.

Castle Precision Incubator No. 554, Illustrated, is recommendedfor milk analysis by the agar plate method. Other models invarying capaties for various bacteriological applications areavailable. Write-IWIL T SL1212 UNIVERSITY AVENUE ROCHESTER, N. Y.

SPRAGUE - DAWLEY, INC.|

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LaMotte Outfit for Control of Chlorine

in Swimming Pool Water powers Of nature, sport & huting~~~~~~~~~~glasses,$6. upward. Telescopes, spotting &

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This inexpensive outfit was developed for private pools with guaranteed.tests that can be easily, quickly and accurately made.It is equipped with two chlorine standards representing the I Catalog free,high and low chlorine concentrations (0.2 and 0.5 p.p.m. BoX B.

4

chlorine) recommended for swimming pool water steriliza-tion; necessary reagents, glassware, and full instructions;packed in a special case ready for use. Price $5.00 f.o.b.our laboratory.Also available, a similar LaMotte Outfit for control of pHin Swimming Pool Water. Price $5.00. And a specialset combining the pH and chlorine tests in one case. Price$8.50 f.o.b. our laboratory.

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FOR SALE: Proceedings of the Society for Ex-perimental Biology and Medicine. Vols. 19 (1921)to 43 (1940) inclusive. Bound in buckram, per-fect condition, $85.00, Cincinnati. Address Mrs.Glenn E. Cullen, 255 Loraine Ave., Cincinnati,Ohio.I

SCIENCE-ADVERTISEMENTS 5

Four Centrifuges in One.MICRO -ANGLE - HORIZONTAL - CHEMICAL

INTERNATIONAL "Clinical Model"One reason for the continued popularity of the International "Clinical Model" Centri-fuge is its wide range of usefulness due to the variety of interchangeable heads. Thus,at low cost, this small centrifuge offers the advantage of being practically four centri-fuges in one. Maximum speeds range from 2,000 r.p.m. to 5,800 r.p.m. depending uponthe type of head used and whether operated on A.C. or D.C.

MICRO HEADSfor swinging .5, 1, 2, 3 and 5 ml. glass tubes either at anangle or in a horizontal position.

ANGLE HEADSThe illustration at right shows a streamlined Conical Head forswinging 6-15 ml. glass tubes at an angle. Other ConicalHeads with capacities up to 200 ml. are available.

HORIZONTAL HEADScommonly known as "regular" heads, accommodate 4-15 ml. or50ml. glass tubes or combination of both for horizontal sedimen-tation.

CHEMICAL BASKET HEADSA Basket Ilead and Draining Chamber may be easily inter-changed with the guard bowl and tube carrying heads to makea Chemical Centrifuge. Baskets and Draining Chambers areavailable in manganese bronze, Coors porcelain, monel metal,stainless steel and rubber covered steel.

Send for Bulletin CC or ask your Dealer

INTERNATIONAL EQUIPMENT COMPANY352 Western Avenue Makers of Fine Centrifuges Boston, Mass.

JUNE 20, 1941

0 SC C-A ETIMNTVo.9,N 25

Time Intervals forLABORATORIES of PHYSIOLOGY and PSYCHOLOGY

THE Vibrating Interrupter (one-third the actual size).Adaptable to any frequency from 2 to 100 per second,as well as to 1-second intervals by use of a specialweight.: Non-sparking. Principle of activation: elec-tro-magnetic.repulsion of the flat polarized spring.

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Vob 93, No. 24258. SCIENCE-ADVERTISEMENTS

SCIENCEVOL. 93 FRIDAY, JuNE 20, 1941 No. 2425

Science, National and International, and the Basis of Special Articles:Cooperation: DR. A. V. HILL ........ .............. 579 The Prevention by Choline of Liver Cirrhosis in

Energy at the Threshold of Vision: PROFESSOR SELIG Rats on High Fat, Low Protein Diets: DR. HAROLDHECHT, DR. SImoN SHLAER and MAURICE H. BLUMBERG and PROFESSOR E. V. MCCOLLUM. ThePIRENNE ....585 Metabolism ofof-Naphthylamine by Rats, Rabbits

Scientific Events: and Monkeys: K. DOBRINER, K. HOMANN and DL.ThienfCollegensofaSurgeons, London;NatureProtec-. P. RHOADS. Bacteriaemia in Land-Locked Sal-The College of Surgeons, London; Nature Protec- mnon (Salmo sebago) in Maine: DR. E. CLIFFORDtion and Wildlife Preservation; The Scientific Ap- NELSON and DR. S. F. SNIESZ:O. E . 598paratus Makers of America; The Hundredth Anni-versary of the College of Literature, Science and Scientific Apparatus and Laboratory Methods:the Arts of the University of Michigan; Celebra- A Design for a Saturated Calomel Electrode: PRO-tion at Butgers University; Honorary Degrees Re- FESSOR M. GARCIA BANUS. A Convenient Methodgently Conferred on Scientific Men. Deaths and of Labeling Bottles: PROFESSOR E. WILBUR COOK,Memorials .587 JR. How to Remove the Plungers of "Frozen"

Scientific Notes and News ..... ............... 590 Glass Syringes: W. R. GOFF ....... ................ 601Discussion: Science News. 8The Manchester Literary and Philosophical So-ciety: PROFESSOR DONAL SHEEHAN. The Age of SCIENCE: A Weekly Journal devoted to the Advance-Sauropod Dinosaurs: DR. BARNUM BROWN. West- meant of Science, edited by J. MCKEEN CATTELL and pub-ward Spread of Eastern Type Equine Encephalo- ledof Friday bymyelitis Virus: LT. COLONEL RAYMOND RANDALL lashed every Friday byand FIRST LT. ERVIN A. EICHHORN. The "Mean- THE SCIENCE PRESSing" of Science: DR. FREDERICK S. HAMMETT ............Pa,593

Lancaster, Pa. G~arrison, N. Y.Scientific Books: L

Algebraic Theories: PROFESSOR CYRUS COLTON New York City: Grand Central TerminalMACDUFFEE. Pharmacy: PROFESSOR CHARLES A. Annual Subscription, $6.00 Single Copies, 15 Cts.KOFOID .. . 596 SCIENCE is the official organ of the American Associa-

Reports: tion for the Advancement of Science. Information regard-Thirtieth Annual Report of the Brooklyn Botanic ing membership In the Association may be secured fromparden, erooyn oanc the office of the permanent secretary In the SmithsonianGarden ..........597.....Institution...............Building,.............WashingtonIsttuiouidigWD.igtn C..C

SCIENCE, NATIONAL AND INTERNATIONAL,AND THE BASIS OF COOPERATION'

By Dr. A. V. HILL, M.P.

FOULERTON RESEARCH PROFESSOR AND SECRETARY OF THE ROYAL SOCIETY

I SHOULD be the last to claim that we scientific men,as a class, are less liable to prejudice on grounds ofself-interest, race, politics or religion than other edu-cated people; and we should deceive ourselves, and per-haps some uncritical members of the public, if we wereto assume (as some of us seem to do) that scientificeminence, or the scientific habit of mind, as such, oreven scientific notoriety, give any special virtue to ouropinions on more ordinary topics. It is, nevertheless,a fact that the nature of our occupation makes scien-tific men particularly international in their outlook.In its judgments on facts science claims to be inde-pendent of political opinion, of nationality, of material

'Read at the Annual General Meeting of the Parlia-mentary and Scientific Committee held in the House ofCommons.

profit. It believes that nature will give a single answer

to any question properly framed, and.that only one

picture can ultimately be put together from the verycomplex jigsaw puzzle which the world presents. In-dividual and national bias, fashion, material advantage,a temporary emergency, may determine which part ofthe puzzle at any moment is subject to the greatestactivity. For its final judgments, however, for itsestimates of scientific validity, there is a single courtof appeal in nature itself, and nobody disputes itsjurisdiction. Those who talk, for example, of Aryanand non-Aryan physics or of proletarian and capitalistgenetics, as though they were different, simply makethemselves ridiculous. For such reasons the commu-nity of scientific people throughout the world is con-

vinced of the necessity of international collaboration;