A NEW TECHNICONmnicroslide cablinet for

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the same light-weightmetal tray. Cabinet unitsore small enough to fiteasily on desk, and can bestacked with existing "LAB-AID" vertical slide-files.

As slides are freshly completed they are put at once into these com-partmented flat-filing trays. The slides are then handled, filed, anddried in the same tray: they need never be removed except for micro-scopic examination. Slides do not contact each other, drying is speedier,cover glasses stay put.

Complete visibility. Each specimen, with its identification data, standsout boldly against the neutral gray background of the tray floor . . . a

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March 9, 1951

Prosser, Brown, Bishop, Jahn and WulffCOMPARATiVE ANIMAL PHYSIOLOGY

This new book is a comparative study of the physiological and bio-chemical characteristics of animals. It represents a monumentalattempt to clarify the evolutionary relationships of various kinds ofanimals and to describe the diverse ways in which they meet theirfunctional and environmental requirements.

A considerable amount of original research and a number of new

theories and generalizations are presented here for the first time.Suggestions for further research are made frequently throughoutthe book. There are 3800 reference items-providing the most com-

plete and unified picture of the literature on comparative physiologyin the English language.The material is organized on a functional rather than a phylogeneticbasis. This type of arrangement, the authors feel, does away with a

great deal of unnecessary duplication.The book will prove ideal as a text for courses in ComparativePhysiology at the advanced undergraduate and early graduatelevels. It will furnish the physiological material for courses on

special groups of animals. Besides its textbook uses, it is also in-tended as a source book for reference use by teachers in related fieldsand by beginning investigators.Edited by C. LADD PROSSER. By FRANK A. BROWN, JR., Professor of Biology, North-western University; DAVID W. BIsHOP, Professor of Physiology, University ofMassachusetts; THEODORE L. JAHN, Professor of Zoology, University of Californiaat Los Angeles; C. LADD PROSSER, Professor of Physiology, University -of Illinois;and VERNER J. WULFF, Assistant Professor of Physiology, University of Illinois.888 pages, 6" x 91/s", with 312 illustrations. $12.50 New

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The Densichron's extreme accuracy. small size. and likht weightqualifies it for use in many of today's light-measuring opera-tions in graphic arts work, scientific research, and industrialprocesses control. Precise density determinations with theDensichron in photography and printing allow for the estab-lishing of reproducible standards in all light measuring phasesof this work.The Densichron's ability to measure accurately the light in-tensity of the smallest details in photomicrography enables theresearch scientist to resolve the longest exposure times he mayencounter.

In industrial processes control (control of thyratons, relayamplifiers, and timing devices) the output of the standardDensichron may be utilized. This is possible because the out-put is an alternating voltage which is proportional to theamount of light received by the phototube. Control of this

nature is practical in operations requiring strict adherence totolerances, or in any operation which may be so arranged toprovide minute changes in the intensity of the light flux re-

ceived by the Denischron.Specifications: Density Ranges; 0-1, 1-2, 2-3, and 3-4

Light measuring Ranges; 5, .5, .05 and .005 footcandles

Sensitivity Controls; 4 decades by the RangeSwitch with one decade continuous and an

overall control of 10,000 to 1.The instrument comes supplied with blue-sensitive light probe(or red if specified), five measuring apertures, a cone with 1/8inch aperture, and metal support for the probe unit. Thecurrent consumption is 30 watts. For operation on 115v 60cycle A C only.*

Write today for new descriptive folder! Price* Can be supplied for 50 cycle operation at an additional charge of $10.00.

$225.

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SCIENCE, Vol. 113

IU

ii Oh li .QUD %Igjit.

new DhGRAU.HILI sGENERAL ZOOLOGY. New 2nd edition

By TRACY I. STORER, University of California at Davis. McGraw-Hill Publications in theZoological Sciences. Ready in March

A general introductory text for colleges, the second edition of this well-known text has been re-vised for the incorporation of recent developments. Part I consists of general animal biology,including-structure, physiology, reproduction, genetics, ecology, etc. Part II covers the animalkingdom from Protozoa to man. A revised edition of the laboratory manual to accompanyGeneral Zoology will be available.

EXPERIMENTS IN BIOCHEMISTRYBy M. S. DUNN, University of California, and WILLIAM DRELL, California Institute of Tech-nology. In press

A guide to advanced laboratory work, including much more theory and reference data than iscustomary in lab manuals. Covers isolation, synthesis, analysis and determination of biologicalsubstances including amino acids, peptides, etc. Emphasis is in completeness of lab directions,yields and purity of products, precision and accuracy of quantitative data, integration of quali-tative tests for the identification of substances, explanation of chemical reactions, and quality ofresults.

POULTRY HUSBANDRY. New 3rd editionBy MORELY A. JULL, University of Maryland. McGraw-Hill Publications in the Agricul-tural Sciences. In press

Includes recent advances in poultry breeding, housing, nutrition, disease control, marketing,eggs and poultry, and increasing efficiency in production. The text is exceptionally well organ-ized, includes comprehensive discussions of fundamental principles, and cites numerous practi-cal applications.

PHYSIOLOGY OF THE FUNGIBy VIRGL G. LILLY, West Virginia University, and HORACE L. BARNETT, West VirginiaUniversity. McGraw-Hill Publications in the Botanical Sciences. In press

A diseussion of living fungi, their life processes and the factors which influence their-activities.This is the first book of its kind designed to accumulate and coordinate the present informationon the physiological aspects of growth, methods of cultivating fungi, reproduction, parasitismand variation.

Send for copies on approval

$5GRAW-HILL BOEOK COS, I_ ~ ~ I~*~ WEUBY 4 2ND STREE T, NEKW YORK 198,

SCIENCE, Vol. 1134

WARBURG MANOMETER

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0.001 cc volume.* Fits any standard taper Warburg Manometer.

UseThe Warburg Manometer Calibrator is designed to make the calibration of aWarburg Manometer simple, rapid and precise. It is also useful where an ex-tremely accurate fluid or gas volume displacement measurement must be made(pipette, micro-burette). The illustration shows the calibrator affixed to astandard Warburg Manometer ready for calibration.

DescriptionThe calibrator eliminates the older, time-consuming calibration method of fillingand weighing mercury to determine the Warburg Manometer constant. Theoperational principle involves a fluid displacement (water) with a known areapiston by means of a high quality metric micrometer, calibrated in hundredths ofa millimeter. Since the area of the piston is one square cm, each small division isequivalent to 0.001 cc. A plastic top forms the cavity for the measuring fluid(water) which is displaced by the micrometer advanced plunger. This plasticpiece has a 17/20 taper joint to fit the Machlett Warburg Manometer. Any otherstandard taper adapter can be supplied instead at no extra charge. All plastictops of different taper (17/20, 14/20, 14/26) are interchangeable. Only 1 cali-brator required. Measured volumes can be readily computed. All parts, exceptthe micrometer and plastic piece, are of stainless steel with one neoprene rubberseal.Warburg Manometer Calibrator, of stainless steel with one removable plasticstandard taper 17/20, complete (will fit Machlett manometer) $25.00(Supplied at same price with any other size standard taper adapter)Plastic Standard Tapers for use with calibrator 14/20 - 14/26, each $7.50(Specify standard taper desired)* Journal of Laboratory & Clinical Medicine pg 1702, Dec. 1949

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"A survey of the dynamic core of biochemistry suchas is to be found nowhere else . .. of greatest importanceto all those interested in the subject"-

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"The author has purposely stressed the chemical aspects without emphasison the clinical problems. Much of the text is subject to changes as further ad-vancements are made; nevertheless it offers a useful source of information for stu-dents of biochemistry."-Journal of the American Medical Association

"Designed for those who ultimately intend to take an advanced degree in thesubject, the book should also aid those whose interest in biochemistry is mainlythat of the organic chemist or the clinician to maintain a broad general outlook.Every serious student of biochemistry will include this excellent volume in hislibrary."-Yale Journal of Biology & Medicine $5.00

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imp, for 110 and greater accuracy, the new Leitz student micro-rd, switch and scope is ideally suited to teaching requirements.

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Watch for Our New Spring Books!

Robert BACTERIOLOGYBuchanan Fifth Edition

A basic text for the introductory course in Bacteriology for students inthe sciences and allied fields, this book has been rewritten and revised toinclude important neW material. An attempt has been made to put a com-plex subject in simple, readable language. To be published in April

Katherine AN INTRODUCTION TO THEChamberlain SCIENCE OF PHOTOGRAPHY

Here is a book which sets forth the principles of photography and theunderlying physics in a readable nontechnical style for students in begin-ning photography courses or for anyone wishing to study photography onhis own. lust published $4.75

E. E. Stanford MAN AND THE LIVING WORLDRevised Edition

This book covers the chief facts and principles of all the life sciencesand brings out their interrelationships and their particular relationship toman and to the development of civilization. The book is comprehensive inscope and scientifically reliable. To be published in May

Victor R. BASIC HORTICULTUREGardner Revised Edition

This outstanding text for courses in Horticulture has been revised in thelight of recent developments and now includes nine pages of laboratoryexercises, suited to any and all climates. To be published in March

Arthur L. INTRODUCTORY ANIMAL HUSBANDRYAnderson Revised -Edition

A complete discussion of the principles of livestock production indmarketing, with special attention to modern commercial requirements, thispractical text for a basic course in Animal Husbandry has been revised toinclude the latest available information. To be published in May

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WRITE for complete information and a dem-onstration to Bausch & Lomb Optical Co.,642-4 St. Paul St., Rochester 2, N. Y.

97Bausch & Lomb Monochromator

SCIENCE, Vol. 113