Purina OAMMlL Nutrition News

FEEDING LABORATORY RATSBy H. C. Schaefer, Director Purina Laboratory Chow ResearchRats have made a tremendous contribution to the science ofnutrition. They are indispensable for the assay of certainvitamins and the biological assay of other nutrients.The nutrient requirements of laboratory rats are probablybetter known than those of any other animal used in research.Much of the fundamental information on amino acids, vitamins;and minerals was learned from investigations with rats.Purina Laboratory Chow was an outgrowth of this discovery.We recommend Purina Laboratory Chow as the sole ration forlaboratory rats without any supplements. It is an excellentand economical diet for reproduction, lactation and growth.Since the use of diethylstilbestrol in cattle fattening rations,Purina Laboratory Chow is made at one of our mills whereno estrogens are used. As an extra precaution, LaboratoryChow is being biologically assayed to make sure it containsno estrogenic activity. This is of special significance toinvestigators in the endocrine and cancer fields.Laboratory Chow can be obtained in several different formsfor the convenience of the investigator. The Checker formmakes for easy and economical feeding. The meal form isa convenience for drug assays or oral administration fortoxicology studies.For further information about the nutrient content of PurinaLaboratory Chow, please see your local Purina Dealer orwrite to Special Industry Sales, Ralston Purina Company,St. Louis 2, Missouri.

WITH OVER 5,000 DEALERS COAST TO COASTTO SERVE YOU

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New (4th) Edition

Marshall-Lazier

Human Anatomy ll

Here is a beautifully illustrated text for an elementary oBo cks

course in human anatomy. Form and function of thehuman body and the relationship of one part to anotherare explained with unusual clarity.

For the New (4th) Edition special attention has been given to the treatment of the neuro-

sensory system. The organs of common sensation have been combined with the chapter on

the nervous system. The section on the Endocrine System has also been completely re-

written. 25 new illustrations have been added.

More than usual emphasis is placed on the joints and segments. Muscles are described as

functional groups, simplifying the task of the student, and making it easier for him to

remember.

By CLYDE MARSHALL, M.D., Formerly Assistant Professor of Anatomy, Yale University. Revised by EDGAR L. LAZIER,Ph.D., Professor of Zoology, University of California at Los Angeles. 420 pages, 5'/2" x 8'!1", with 329 illustrations.

New (4th) Edition!

Frobisher -Microbiology

This text furnishes a firm foundation in the fundamentals of microbiology for the

beginning student. Part I introduces the student to the 8 groups of microorganisms,describing their size, structure and activities.

Part II presents microscopic methods with full details on how one studies microorgan-isms in the laboratory, how they grow, their biochemical and physiologic aspects.

Immunology is covered in Part III and antigen-antibody reactions discussed. With bac-

teria as the basis, Part IV discusses such biological phenomena as evolution, autotrophy,heterotrophy, photosynthesis, chemosynthesis, ecology of microorganisms, etc. The fifth

and final part pictures the special environments in which microorganisms occur.

By MARTIN FROBISHER, JR., Sc.D., Special Consultant, Bscteriology Branch, Communicable Disease Center, U.S.Public Health Service, Chamblee, Georgia; Associate Professor of Bacteriology, Emory University; Visiting Lecturer,Johns Hopkins School of Hygiene and Public Health. 633 pages, 6" x 9¼/4", with 253 illustrations. $6.00.

Fifth Edition!

W. B. SAUNIDERS COMPANY

West Washington Square Philadelphia 5

SCIENCE is published weekly by the AAAS, 1515 Massachusetts Ave., NW, Washington 5, D. C. Entered at the Lancaster, Pa., Post Office as second classmatter under the act of 3 March 1879. Annual subscriptions: $7.50; foreign postage, $1; Canadian postage, 50g.

2 SEPT9EMBER 1955 395

396 SCIENCE, VOL. 122

aIprecision instruments

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STEREOSCOPICmicroscopes

remarkable clarity and depthLeitz STEREOSCOPIC Microscopes provide a truly three-dimensional imdge of unsurpassed brilliance for examinationsin the industrial and sciertific laborotory. They are engineeredto give precision performance-assembly work on small parts,quality control, examinations in geology, mineralogy and inthe biological field.* Wide field of view * Dual controls * Polarized, transmitted or

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L image quality through unique prism arrangement

HEATINGmicroscopes

prec determination of melting behavior

Simplified, accurate determination of the melting behavior offuel ashes, slogs, glazes, enamels, glass and ceramics is as-sured with the Leitz HEATING Microscope, which permits visualobservation and photographic recording of softening and melt-ing phases. A series of photographs and temperature registra--tions provide laboratory evidence from which the viscosity ofthe specimen may be determined. Accessories avoiloble forincident light examination. Polarized light accessories avail-ebb for strain ond stress analysis under high temperature used

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INU F" t:

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New KodagraphMicroprint Reader makes

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The microprint idea can reduce the largest li-brary to a small set of cards. Sixty conventionalpages can go on a 3 x 5-inch card, with an ab-stract and filing data in ordinary-size type on

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read in complete comfort. The screen is greenand tilted 110 because that's the combinationthat seems to be easiest on the eyes. It's brightenough to use in ordinary room light. Severalpeople can read at a time.You feed microprint cards into a Kodagraph

Microprint Reader like paper into a typewriter-any size up to 812 x 14 inches.Many publishers offer microprint card edi-

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EASTMAN KODAK COMPANY 65

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Please send me the information checked:

| Where I can see a Kodagraph Micropriti Re?ader.CD Folder on the Reader and sample micraprint card.

EJ List of publishers of microprint cards ar.J manufacturersof microprint cards to order.

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* Isopalmitic Acid

* Isoprene Sulfone* Isopropylhydrazine

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* Juglone* Kaempferol* Keratin* Ketene Dimer* x-Keto-b-aminovaleric

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MIODEL GB2 All metail constructionA full fine adjustment with

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Achromatic objectives16 mm (lOX) N.A. 0.274 mm (44X) N.A. 0.66

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5 or more. $106.20each

Old instruimentsaccepted in trade

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>SSCIEN'CE, VOL. 1"22

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Projects vivid true-colorscreen images for a solid hourwithout interruption!

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Basic Illuminating Stand can be used, as shownhere, with any microscope which has a substagecondenser. Completewith built-in clamp-ing device, built-infixed mirror, Balcot-ed projection eye-piece, prism andlight shield, $376.

See for yourself inFREE DEMONSTRATION !WRITE today for your free demonstration and for yourcopy of informative Catalog D-246. Bausch & Lomb Opti-cal Company, 64273 St. Paul St., Rochester 2, New York.

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SCIENCE. VOL. 122400

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