CENTRIFUGE MODEL CLfor both chemical andanalytical centrifuging

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The \fodel CL C(entrifuge is axTailable in a %vide varietN of licadlslangleor hoirizontal) for tube capacities uip to 50nOl, at variotus speed,¢ andiforces, for smnall sample analy sis. B}asket heads and(i dIraiiiingt chiatnmbersare av ailable in manganese bronze. stainless steel. tlonel imetafl.rubber-cox ered steel or porcelain, for resistance to s 1hatc\ er so'lutionwyoui eflploy.Other feattires include: guar(l box Is enclosing all rotatilg }'artr; .pecdcoIntrol rheostat in base: reliable AC-tDC Iiotor. r'ie Mtodel C:L is listedby t ndcer- riters" Laboratories. Sendefor Bulletinz DS.

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New (3rd) Edition! W'eatherwNaxoBtanyHere is an ideal text that fully meets the demands of current educa-tional trends-that of shorter courses with broader coverage. Beauti-fully illustrated, it is a concise presentation of the principles ofbotany. It contains all the material necessary for a one semestercourse presented in an easily understandable manner. This New(3rd) Edition has been divided into two sections-General Principlesand The Plant Kingdom. The first 22 chapters clearly illustrate theprinciples of biology with examples from the plant kingdom. Thesecond part of the text deals with specific groups of plants, enablingthe student to recognize major groups. He also learns how to applythe general principles discussed in the first part of the book tospecific cases.

By PAUL WEATHERWAX, Professor of Botany, Indiana University. 509 pages, 6" x 9¼4", with305 illustrations. $5.75. New (3rd) Edition!

New! Witschi-eDvelopment of VertebratesThis new book presents an excellent comparative study of the lifecycles of amphibians, fishes, reptiles, birds and mammals. One-thirdof the book is mammalian embryology and about one-half of this isdevoted to human development. The book aims to help your studentssee that development is a natural process open to scientific researchmethods, not essentially different from the inorganic sciences. Thebook opens with an explanation of the basic concepts of embryologyand a clarification of technical terms. The deviations among theclasses and species are fully described. This gives the student aninteresting and understandable picture of the complicated composi-tion of living organisms. Especially helpful are the many clear illus-trations.By EMIL WITSCHI, Professor of Embryology and Endocrinology, State University of Iowa. 588pages, 6" x 9¼4", with 370 illustrations. $8.50. New.

Frobisher MicroiologyIn its Fifth Edition, this text presents microbiology in the mostmodern, orderly and logical way possible. The first part of the bookintroduces the student to the eight groups of microorganisms. PartII gives the student a working knowledge of the subject-micro-scopic methods; how to study microorganisms in the laboratory, etc.Part III, covers antigen-antibody reactions. With bacteria as thebasis of discussion, Part IV includes such phenomena as evolution,autotrophy, chemosynthesis, parasitism, etc. Part V explains thespecial environments in which microorganisms occur.

By MARTIN FROBISHER, JR., Sc.D., Special Consultant, Bacteriology Branch, CommunicableDisease Center, U.S. Public Health Service, Chamblee, Georgia; Associate Professor of Bacteriol-ogy, Emory University; Visiting Lecturer, Johns Hopkins University. 633 pages, 6%" x 9¼", with253 ilustrations. $6.00. Fifth Edition.

West Washington Square PhiladelphiaSCIENCE is published weekly by the AAAS, 1515 Massachusetts Ave., NW, Washington 5, D.C. Entered at the Lancaster, Pa., Post Office as second class

matter under the act of 3 March 1879. Annual subscriptions: $7.50; foreign postage, $1; Canadian postage, 50¢.

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14 SEPTEMBER 1956 463

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Labolux A new concept in microscope design combining coarseand fine focusing adjustments in a single control, resulting in utmostsimplicity and convenience. Low-position controls for fatigue-freeoperation. Stage, not tube, moves for focusing. May be used facingthe observer for greater accessibility to all controls.Labolux S 47/92-15 Built-in mechanical stage; Abbe condenser; quadruple nosepiecewith achromats 3.5x, lOx, 45x, 1OOx oil -the two high-powered objectives havespring-loaded mounts; paired 6x and lOx eyepieces; including professional carryingcase: $637.50

Monocular-Binocular Model "B" A convertible microscope of classicdesign with ball-bearing fine adjustment, trouble-free operation,triple or quadruple nosepiece with magnification range from 21to 1000 times. Unique dove-tail slide permits quick interchangeof tubes.

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Monocular Microscope Model "G" A first-class precision instru-ment with full-size laboratory stand, large diameter monoculartube. Full range of plain and mechanical stages available, as wellas triple or quadruple nosepiece.GO 47/92-10 Monocular; mechanical stage; Abbe condenser; triple nosepiece withachromats lOx, 45x, 100x oil; 6x and lOx eyepieces; including professional carryingcase: $352.00

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The multiplex anomalies andvariations in the blood supply tothe upper abdomen-graphic-ally delineated in colored draw-ings with explicit descriptivetext. Twenty years in the mak-ing-the only atlas of its kindin the world! A good portion ofyour life might be spent inlearning what this unique bookhas to teach.

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14 SEPTEMBER 1956 501