A · for old mice, rats, etc., 16 penny (3i inch) nails; for guinea pigs, rabbits, ground squirrels, etc., 30 penny ... host in order to invade instantly the mucous mem-branes. The

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -A

NEW SERIES SUBSCRIPTION, $6.00VOL. 86, No. 2242 FRIDAY, DECEMBER 17, 1937 SINGLE COPIES, .15

WHEN ORDINARY METHODS ARE TOO

SLOW USE SPECTROGRAPHIC EQUIPMENT

7t,HEN both speed and accuracy are essential-when other methodsare difficult or uncertain-then spectrographic procedure proves

its true value.With B & L Spectrograplhic equipment you can obtain qualitative analysis ofmaterials quickly and accurately, identify all constituents and determine theamount of impurities. All details of the complete analysis may often be ob-tained from a single, easily interpreted photograplhic plate. Numerous labora-tories are relying on B & L Spectrographic Equipment for this vital information.They select B & L Equipment because matched B & L accessories enable themto get the most out of their spectrographic work.Catalog D-20 contains valuable information on spectrographic methods, applica-tions and equipment. Write for it to Bausch & Lomb Optical Co., 642 St.Paul Street, Rochester, New York.

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Entered a8 second-cla88 matter July 18, 1923, at the Post Office at Lancaster, Pa., under the Act of March 3, 1879.

I L

2 CEC-DETSMNT O.8,N.24

IBIOLOGICAL MATERIALSAA

LIVE MARINE AQUARIA SETSWith the successful practice for the past seven years of shipping bal-anced Marine Aquaria Sets, the Supply Department has made it pos-sible for the inland student to have the advantages of those working near the coast whereliving material is readily available.

The service of supplying live specimens to schools located at some distance from the seahas proven very satisfactory, and successful shipments as far west as the Mississippi andas far south as Georgia are guaranteed from November through February. Our rec-

ords show that these live aquaria sets have arrived in good condition in New Mexico,Texas, Missouri and other western states, but shipments to such distant points are notguaranteed.

These Marine Aquaria Sets are listed in our new 1937 catalogue in which prices on both living andpreserved specimens have in many cases been greatly reduced.

Supply Department Marine Biological Laboratory Established 1890Woods Hole, Mass.

Temperature Controlled CentrirugalizationComplete with its own refrigerating unit,

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solid and liquid phases can be separated at

rigidly controlled temperature from 3 2 °-8 00IF r --g_g; W :;;X-:X;;;;?:F.Tropical climate or seasonal changes have

no effect on its operation.The Refrigerated Centrifuge replaces to ad-

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which these are slow. It avoids the possibilityof contamination by prolonged exposure dur-ing filtering and prevents the development of

fermentation or other changes. It obviatesthe need of using rapid high power filtration.

Alcohol, ether or other volatile substances can

be used with safety in this centrifuge.Illustrated Descriptive Bulletin

THE REFRIGERATED CENTRIFUGE upon Request

INTERNATIONAL EQUIPM ENT COM PANY352 Western Avenue Makers of Fine Centrifuges Boston, Mass.

rVOL. 86, No. 22422 SCIENCE-ADVERTISEMENTS

DECEMBER 17, 1937 SCIENCE-ADVERTISEMENTS S

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The Empire Autotechnicon automatically transfers tissues through fixing,dehydrating, clearing and impregnating fluids. It is electrically motivated,set into operation by a single movement ofa switch. A special timing discenables the technician to fix the length of time during which the tissuesare to remain immersed in the various fluids. The time may be the sameor different for every fluid and can be varied from 7% minutes to 48 hours.

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INDICATORS

The Coleman & Bell Companymanufacture a complete list of in-dicators including all of the com-mon indicators used in analyticaland biological work, the hydrogen-ion indicators recommended bySorensen and Clark & Lubs, and in

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Catalogue of Laboratory Reagents Upon Request

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LaMotte pH Test PapersAs an aid in the approximate estimation of the pHof various solutions and substances, we have pre-pared a series of sensitive test papers from ourstandardized pH indicators. They are supplied invials containing 100 strips of the paper and areavailable within a range of 3.8 pH to 9.6 pH. Price50 cents per vial for each indicator range-F.O.B.Baltimore, Md.

LaMotte Chemical Products Company418 Light St. Baltimore, Md.

A Stereoscopic Atlas of the ChickConsists of 113 three-di-mensional photographicprints of stages from theprimitive streak to thefourth day of incubation,both of whole embryos andof progressive stages ofdissection. Very valuablematerial for prolongedstudy and largely replaces

_ _ the use of sections. Price,complete with stereoscopeand box, $7.35 delivered.Sent on approval.California Laboratory Supply

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DECEMBER 17, 1937 SCIENCE-ADVERTISEMENTS 5

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6 SCIENCE-ADVERTISEil[ENTS VOL. 86, No. 2242

VOL. 86, No. 2242

We have used common nails with complete successand have found that the following sizes are the mostconvenient for the experimental animals designated:for old mice, rats, etc., 16 penny (3i inch) nails; forguinea pigs, rabbits, ground squirrels, etc., 30 penny(4i inch) nails; and for ferrets, monkeys, woodchucks,etc., 60 penny (6 inch) nails.

The procedure of intracerebral inoculation, asroutinely carried out in our laboratory with the in-strument just described, is as follows. The site to beinoculated is usually in the parietal region overlyingthe right cerebral hemisphere, midway between theexternal canthus of the right eye and the externaloccipital protuberance. Following anesthetization ofthe experimental animal and suitable preparation ofthe skin, a small incision is made through the skin ashort distanee to one side of this mid-parietal site. Thepoint of the instrument is inserted through the skinincision, the scalp is retracted with it, and the skull ispenetrated at the site described. The point of theinstrument is left in place in the skull and the needleof the syringe containing the suspension to be injectedis slid along the groove until, penetrating the skullbeside the point, it enters the cerebral cortex. Thedesired amount of inoculum is injected, and the needleand the instrument are withdrawn together. Follow-ing withdrawal, the retracted skin, by immediatelyrebounding, provides a satisfactory covering for theopening through the skull.

JEROME T. SYVERTONGEORGE PACKER BERRY

UNIVERSITY oF ROCHESTERSCHOOL OF MEDICINE ANDDENTISTRY

FILTER-METHOD FOR CLEAN ISOLATIONOF TRICHINELLA-LARVAE

IT is well established that Trichinella-larvae havingentered the stomach move to the small intestines of thehost in order to invade instantly the mucous mem-branes. The following procedure makes use of thisactivity of the larvae as it is done in the Bearman-method.

The neck of a glass funnel is transversally cut anda perforated rubber stopper slipped over the stumpin order to hold a test-tube (centrifuge) in a water-tight position. The funnel rests on a tripod ring(see Fig. 1). A cylindrical fruit (Mason) jar, smallerin circulmference than the funnel, a fitting glass cover,four layers of gauze and a rubber stopper (the latterin order to close the inner opening of the funnel, ifdesired) may be kept ready.For use, both funnel and test-tube are filled with

tap water (2 per cent. sodium chloride solution ispreferable). Thoroughly minced Trichinella meat ismixed with digestion fluid and filled into the jar. Its

FIG. 1

top is then covered with four layers of gauze, which istightly ligated around the rim. The glass cover isnow pressed against the gauze filter and the jar placedupside down into the funnel. After the cover hasbeen cautiously removed the jar rests in an uprightposition in the funnel. The apparatus remains undis-turbed in the incubator.After completion of the digestion the glass cover is'

inserted, the jar removed, the inner opening of thefunnel closed with the aid of the rubber stopper, andthe fluid in the funnel decanted. More recently weomit the use of glass cover and rubber stopper forthese operations without disadvantage. The sedimentin the test-tube contains the total amount of livingTrichinellas of the digested meat free- from coarse

particles. Further operations follow the ordinarymethods.

M. HOBMAIERK. F. MEYER

HOOPER FOUNDA~IONFOR MEDICAL RESEARCH,

UNIVERSITY OF CALIFORNIA,SAN FRANCISCO

BOOKS RECEIVEDANDERSON, WILLIAM B. Mechanics and Heat. Third

edition. Pp. ix + 378. 226 figures. Sound, Electricityand Magnetism, Light. Third edition. Pp. x + 361-796. Figures 227-534. McGraw-Hill.

AUSTIN, E. E. Bombyliidae of Palestine. Pp. ix + 188.Illustrated. British Museum (Natural History). 15s.

BENEDICT, FRANCIS G. and ROBERT C. LEE. Lipogenesisin the Animal Body, with Special Reference to thePhysiology of the Goose. Pp. vi + 232. 30 figures.Carnegie Institution of Washington.

MELANDER, LEONARD. Source Book of Biological Terms.Pp. 157. College of the City of New York. $1.10.

NORMAN, J. R. Illustrated Guide to the Fish Gallery.Pp. x + 175. 100 figures. British Museum (NaturalHistory). is, 6d.

ROBERTS, MICHAEL. The Modern Mind. Pp. 284. Mac-millan. $2.75.

The Collecte.d Papers of George Ashley Campbell. Pp.xii + 548. Illustrated. American Telephone and Tele-graph Company, New York.

0-68 SCIENCE

DIEME 1, 97 CENE-DERIS M NT

Biologist \/ Zoologist /Entomologist-'BotanistV Geneticist or Naturalist

You, too, must read"Genetics and the Origin of Species"Tb. Dobzhansky's new book on Organic Diversity,Gene Mutation, Mutation as a Basis for Racial andSpecific Differences, Chromosomal Changes, Variationin Natural Populations, Selection, Polyploidy, Isolat-ing Mechanisms, Hybrid Sterility, Species as NaturalUilits.-No. 11, Columbia University Biological Series.

In my estimationwrites T. D. A. Cockerell in Science (Nov. 19, 1937),"if is the best book on these subjects ever written ...

because, being thoroughly well done, it includes the re-sults of so many important recent researches, and sobrWngs us up to date...."

Published on October 23rd, 303 copies were boughtbefore the first review, which is quoted above, ap-peared, and in spite of the fact that only geneticistsar-d zoologists had received an announcement of itspublication.

Textbook possibilitiesAt the moment of going to press with this announce-ment, Genetics and the Origin of Species has beenadopted as a text or as required reading at the uni-versities of Brown, California, Cornell, Indiana, Mc-Gtll, and Pennsylvania. It is being considered as atext by teachers at twenty-three other well known in-stitutions, name on application.In the opinion of L. C. Dunn, Professor of Zoology atCGlumbia and editor of the Columbia Biological Series,t4e book can be understood by any one with a back-ground of general biology.

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Available for examinationyou fill out and mail the coupon below at once, you

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Ready in JanuaryA COLLEGE COURSE INSOUND WAVESand ACOUSTICS

By M. Y. COLBYProfessor of PhysicsUniversity of Texas

The purpose of this text is to givestudents a thorough foundation in theelementary principles of wave motion,objective sound, and acoustics. It pre-supposes only an introductory coursein general college physics. Stress isplaced on the application of principlesto actual industrial practice; and forthis reason a more extended treatmentis given to such topics as beats andcombination sounds, and architecturalacoustics. The plan and content ofthe text are based on fifteen years ofexperience of classroom teaching of thecourse.

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"This book is, without question, one of the bestsolutions so far proposed for the difficult educationproblem of providing teachers and.students with asimple but adequate and consistent transition be-tween elementary and advanced chemistry.I-Pierre Van Rysselberghe, Stanford University, inThe Journal of Chemical Education.

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University of Texas$2.80

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v DEcEMBER 17Y 1937 SCIENCE-ADVERTISEMENTS 7