SCIEN CE- JoNEW SERIES FRIDAY FEBRUARY15 1935 SUBSCRIPTION, $6.00VOL. 81, No. 2094 FIA,FBUR 15195SINGLE COPIES, .15

F the excellence of microscope optics is to be fully utilized,precise construction of mechanical parts is absolutely necessary.

The B & L Centrifuge Microscope is evidence of the Bausch& Lomb mechanical ability. With this instrument you see acontinuous picture of micro-organisms being centrifuged at therate of 10,000 r. p. m.

The specimen is traveling four miles per minute and is sub-jected to a centrifugal force equal to 12,000 times gravity!

The H S E Microscope shownabove is one of the new H series.Binocular vision, divisible bodytube, and 115 x 130 mm stageare characteristics of this instru-ment. It is bulit with the samemechanical precision as the Cen-trifuge Microscope.

The Centrifuge Microscope is a mechanical as well as an opti-cal achievement- and the same mechanical excellence is builtinto every B & L instrument.

For information on the Centrifuge Microscope or other B & LOptical Instruments, write to Bausch & Lomb Optical Company,642 St. Paul Street, Rochester, New York.

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Enitered as second-class matter July 18, 1923, at the Po8t Office at Lancaster, Pa., under the Act of March 3, 1879.

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2 A3OIENGE-ADVERTISEMENT,S. VOL.

THE JOURNAL OF NUTRITIONPublished monthly by The Wistar Institute

John R. Murlin, Managing Editor, University of Rochester

Vol. 9 No. 3 to be issued in March will contain the following articlesROBERT S. HARRIS and JOHN W. M. BUNKER. The phytin phosphorus of the corn component of a

rachitogenic diet. One figure.JOHN C. KRANTZ, JR. and a. JELLEFF CARR. A statistical study of the metabolism of the fasting albino

rat. One figure.SAMUEL H. BASSETT. Mineral exchanges of man. V. Balances of electrolytes in a case of hyperpara-

thyroidism. Five figures.SAMUEL H. BASSETT and HELEN VAN ALSTINE. Mineral exchanges of man. VI. The effect of extirpa-

tion of a parathyroid tumor on the balances of electrolytes. Four figures.E. H. HUGHES and H. G. HART. Production and composition of sow's milk.ALAN C. BURTON. Human calorimetry. II. The average temperature of the tissues of the body. Three

figures.ALAN C. BURTON and JOHN R. MURLIN. Human calorimetry. III. Temperature distribution, blood flow

and heat storage in the body in basal condition and after ingestion of food. Four figures.A. F. MORGAN, L. KImMEL, A. FIELD and P. F. NICHOLS. The vitamin content of Sultanina (Thomp-

son Seedless) grapes and raisins.A. F. MORGAN, A. FIELD, L. KIMMEL and P. F. NICHOLS. The vitamin content of figs.

Price, $5.00 per volume, Domestic; $5.50 per volume, ForeignTwo volumes issued annually

Back volumes from 1 to 8, inclusive, may be had for $40.00

Address subscriptions to

The Wistar Institute of Anatomy and BiologyPhiladelphia, Pa., U. S. A.

TheFoundations of Science

By H. POINCAREPp. xi + 553.

Containing the authorized En-

glish translation by George

Bruce Halsted of "Science and

Hypothesis," "The Value of

Science" and "Science andMethod," with a special preface

by Poincare, and an introduc-tion by Josiah Royce. Price,

postpaid, $5.00.

THE SCIENCE PRESSGrand Central Terminal New York, N. Y.

BOSTON UNIVERSITY

SCHOOL OF MEDICINE

ORGANIZED IN 1873

ANNOUNCEMENT

may be obtained by application to

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80 East Concord Street

Boston Massachusetts

2 SCIENCE-ADVERTISEMENTS VOL. 81, NO. 2094

Ctn i/LLS Ira/tonof the importance of highnumerical aperture of theWHOLE OPTICA L

PHOTOMICROGRAPH A

I HE resolution of a microscope opticalsystem is determined by the lowest

numerical aperture of any of its elements.The Spencer Abbe Condenser of theSpencer Laboratory Microscope No. 33has a numerical aperture as large as1.25 which matches the numerical aper-ture of the oil immersion objective andproduces a "Balanced" Optical System.

The two photomicrographs above areidentical EXCEPT . . the resolution hasbeen deliberately destroyed in Photomi-crograph B by reducing the numericalaperture at one point in the system.

For laboratory or medical work, pur-chase a Spencer No. 33 Microscope. Ithas sufficiently high numerical apertureat ALL points in the optical system toresolve detail as shown in Photomicro-graph A.

Folder M-61 completely describesthe Spencer No. 33 Microscope.Address Dept. A-2 for your copy.

BUFFALO NEW YORK

SYST EM

PHOTOMICROGRAPH B

SPENCER MICROSCOPE NO. 33-MH

FEBRUARY 15, 1935 SCIENCE-ADVERTISEMENTS 3

4 SCEC-DETSMNSVL.8,N.29

MICRO PRTOJECTORXB NEW MODEL

Microprojector XB withhorizontal object stage.

Microprojector XB withvertical object stage.

This efficient Micro Projector which has recently been redesignedoffers the following

OUTSTANDING ADVANTAGAES:1. The entire equipment including Microscope forms one unit of utmost rigidity with

all parts accurately aligned In respect to each other assuring greatest simplicityof operation.

2. Due to Its compactness, the projector Is entirely portable.S. New automatic arclamp of high Intensity.4. A large cooling cell prevents danger of damage to the preparation by heat.

5. The apparatus Is arranged for projection with the object stage of the microscopeIn horizontal or vertical position.

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7. Greatest brillancy of the projector Image at low and high magnification Insuredby an Illumination system of utmost efficiency.

Write for descriptive bulletin.

E. LEITZ, IINC., ]Dept. 66660 East 10th St., New York

Branches: Washington, D. C. ::Chicago, Ill. ::San Francisco, Calif. ::Los Angeles, Calif.

4 SCIENCE-ADVERTISEMENTS VOL.. 81, NO. 2094

FEBRUARY 15, 1935 SCIENCE-ADVERTISEMENTS

New McGraw-Hill BooksBriscoe's The Structure and Properties of Matter

By H. T. BRISCOE, Indiana University. International Chemical Series. 414pages, $3.75

This new book attempts to interpret, from the chemist's The most recent advances, such as the isotopes of hydro-point of view, some of the facts and opinions concerning gen, heavy water, cosmic radiation, and artificial radio-matter as they have been discovered or suggested from activity, are fully treated. Modern principles of wavethe time of Aristotle to that of Bohr and Schrodinger. mechanics are also explained.

Stock and Sta-hler's Quantitative Chemical AnalysisBy ALFRED STOCK, Professor in the Technical High School at Karlsruhe, andARTHUR STXHLER, University of Berlin. Translated from the fourth Germanedition by WINTON PATNODE, General Electric Company, and L. M. DENNIS,Cornell University. International Chemical Series. 176 pages, $1.75

Written primarily from the standpoint of methods and in inorganic quantitative analysis, with the exception ofprocedures, this college laboratory course covers essential gas analysis. Details of apparatus and manipulation aretheory and gives examples of all important methods used given.

Osborn's Physics of the Home. A Textbook for Students ofHome Economics. New third edition.

By FREDERICK A. OSBORN, University of Washington. McGraw-Hill EuthenicsSeries. 441 pages, $3.00

A thorough discussion of those principles of physics electricity in the home, radio, etc. In the new edition,which have direct and constant applications in everyday although the general plan and character remain the same,household work. Takes up heating and ventilating sys- much of the material has been rewritten to bring it uptems, home lighting, the contrast and harmony of colors, to date.

Marsh's Principles of Phase DiagramsBy J. S. MARSH, Associate Editor, Alloys of Iron Research. Alloys of Iron Re-search, Monograph Series. 198 pages, $3.00

It is the intention of this book to offer a strong ground- mean and how they are evolved, the book covers singu-ing in the principles of phase theory, as well as a clear lary and binary systems, ternary systems and systems ofunderstanding of ternary diagrams. In addition to a more than three components. About 180 diagrams arelucid, accurate demonstration of what phase diagrams given.

Groggins' Unit Processes in Organic SynthesisEdited by P. H. GROGGINS, Senior Chemist, Color Laboratory, U. S. Departmentof Agriculture. Chemical Engineering Series. 689 pages, $5.50

Gives a systematic presentation of the principles and amination of the reactants and the mechanism of theproblems of the more important and well-defined reac- reaction. The material also includes observations regard-tions in organic synthesis as they are found in actual ing the design and construction of equipment and illus-plant practice. Particular attention is given to the ex- trative technical applications.

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SCIENCE-ADVERTISEMENTS

WANTEDMANAGER to handle high-grade line of microscopesand optical instruments, also familiar with scientificspecialties. Satisfactory arrangements can be made withthe right person. Applications will be treated strictlyconfidential. Address: C. N. G., c/o Science, 3941Grand Central Terminal, New York, N. Y.

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MANUAL OF TIESOUTHEASTERN FLORA

ILLUSTRATED

Being Descriptions of the Sed-Plants growing naturally in North Carolina, South Carolina,Georgia, Florida, Alabama, Mississippi, Tennessee and Eastern Louisiana

ByJOHN KUNKEL SMALL

T HIS Manual replaces the author's Flora of the Southeastern United States,published in 1903 (second edition 1913), for the Southern States east of the

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In addition to analytical keys to the various plant groups, and descriptionsof the orders, families, genera, and species, regional or altitudinal and geographicdistribution, there are xxii + 1554 pages and over 1500 illustrations, one illustra-tion of a species of each genus.

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THE NEW YORK BOTANICAL GARDEN

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FF,BiauAmy 15, 1935 7