100 ua, 1 ma, and 10 ma. A continu-ously variable degas circuit is providedfor heating the ionization-gage grid. Aprotection circuit safeguards againstvacuum failure. This circuit will turnoff a bank of three a-c outlets with atotal capacity of 3 amp when actuated.The actuation point can be adjustedfrom approximately 5 to 10 times thefull-scale reading on the pressure scaleon which the control is operating. Athree-station unit is available in whichseparate heating and degas circuits areprovided and a single switch enablesthe operator to select any one of threegage stations for observation. The pro-tection circuit is tied in with the par-ticular gage station being monitored atthe time.-J.s. (Nuclide Analysis As-sociates, Dept. S351, P.O. Box 752,State College, Pa.)

Ruby laser modulation system usinga Kerr-cell shutter is designed primari-ly for application in optical harmonicgeneration, optical ranging, and ma-terials research. The nitrobenzene-filledKerr cell can be incorporated with-in ruby-laser cavities as a Q spoiler foroperation of the laser in the pulse re-flector mode or in a number of otherpossible modes. The Kerr cells arehermetically sealed and are providedwith integral expansion bellows. Win-dows are guaranteed to be flat within1/4 fringe over the useful aperturefrom 0.25 to 0.6 inches. The completesystem includes control console andpower supply, remotely operating mod-ulator pulse generator, and appropriatevoltage shaping network.-J.s. (Elec-tro-Optical Instruments, Inc., Dept.S358, 2612 E. Foothill Blvd., Pasadena,Calif.)

Specialized and scientific photo-graphic equipment makes this latestcatalog from Burke & James of realvalue to the industrial and scientificphotographer. Micro- and macrophotog-raphy equipment, cameras for pathol-ogy and copying equipment, as wellas complete listings of "lens bank"services and lenses, laboratory anddarkroom needs, and temperature con-trol systems are only a few of theequipment categories covered. This isthe biggest and most complete catalog(148 pages) ever published by Burke &James. The 65th annual catalog fromthis supplier is a valuable referencesource for the photographic specialist.It is available free on request.-R.L.B.(Burke & James, Inc., Dept. S309, 321South Wabash, Chicago 4, Ill.)7 SEPTEMBER 1962

detect and continually record...

PROTEINS

with the T E C H N I C O N 0

You can now automatically analyze or monitor...

* FOOD PRODUCTS such as flour, gelatins, dairy products,meat products, beverages, etc.

* PHYSIOLOGICAL FLUIDS and TISSUEHOMOGENATES

* FERMENTATION PROCESSES in industriesfor

Total Protein, Albumin, Globulin, etc.

*Detects other elements or compounds too: e.g., Hydrazine,Ammonia, Chromium, Cholinesterase, etc. 65 fully-auto-mated determinations now possible . . . more are coming.

Send for your free abstract method kit and brochure AK today

TECHRICHONPONTROLC, INC.RESEARCH PARK * CHAUNCEYt N. Y.

ERB & GRAY SCIENTIFICis pleased to announce

the appointment of

MR. ROBERT SEIBERTas District Manager for Erb & GrayScientific for the Gulf States, plusOklahoma and Georgia.

Mr. Seibert can be contacted at

441.0 RICHMOND AVE.HOUSTON 27, TEXAS

ERB & GRAY SCIENTIFICA Division of The Perkin-Elmer Corporation

home office: 854 S. Figueroa St., Los Angeles 17, Calif.

5927 Riverdale Ave.New York 71, N. Y.

1103 Westgate Ave.Oak Park, Illinois

4410 Richmond Avenue, Houston 27, Texas

775

IMPORTA:NT- NORELCOFEATURES IN

ELECTRON

Norelco Electron Micro-scopes-EM-75, EM-100 or

EM-200, all have a com-mon and exclusive featurewhich is unusual in design.

This feature provides _-facilities for conductingmicroscopic investigationswhich are essential because of the flexibility andlatitude with which specimens may be observed.

A direct-line immer-

sion-type objective lens,conceived by Philips'optical engineers with

al = years of experience,allows for samples to bepositioned at the end ofthe specimen rod andthen "immersed"directly into the heart ofthe objective lens. The

i-W resulting versatility isunbelievable. Specimensmay be angulated andmanipulated for orien-

tation, temperature and tensile studies. Even hygro-scopic materials such as Phosphorous Pentoxide(P205) may be dry-boxloaded and transferred tothe microscope withoutatmospheric contact. It isalso possible to handle

'Itwo or more samplessimultaneously for com-parative studies or for ex-pediting the microscopists'work-load.

ELECTRON OPTICSFor more detailed information write to:

EPHILIPISEX&E3CTROM IC INX T3RXYJME NTSA Division of Philips Electronics and Pharmaceutical Industries Corp.

Dept. EM-2, 750 South Fulton Ave., Mount Vernon, N.Y.

BIRD RESPIRATION PUMPSingle piston-for producing artificial breathing insmall animals. The valve is synchronized with thestroke to control air flow direction. When the pumpreaches full travel on the pressure stroke, the valve dis-connects the flow of air to the lungs and exhalationtakes place naturally. Gas mixtures may be introducedor collected through the valve system. For best results,use our #71-021 cannula.

Available in three models.#70-878-01 #70-878-02 #70-878-03

Rate 15-140 strokes Rate 40-200 strokes Rate 7-34 strokesper min. per min. per min.

Vol. .7.50cc per stroke Vol. 0-1.5ce per stroke Vol. .7-50ce per stroke

LPUUULPLJ11. L)ED aM D 00 (30Manufacturers & Distributors of Scientific Equipment6th & Byrd Streets- Richmond, Virginia

SCIENCE, VOL. 137

AGING ...Some Social and Biological AspectsA symposium presented at the AAAS

Chicago Meeting

December 1959. Published November 1960.Nathan V. Shock, Editor

6 x 9, 436 pp., 65 illus., cloth$8.50 AAAS members' cash orders $7.50

CONTENTSImplications for society: J. W. McConnell, J. T. Freeman,

R. J. Havighurst, C. D. Leake, S. SpectorAging in tissues and cells: B. Glass, J. D. Ebert, G. H.

Bourne, A. WhiteAging in the total organism: M. Landowne, G. Pincus, P.

Handler, E. W. BusseTheories of aging: N. W. Shock, H. Selye, P. Prioreschi,

B. L. Strehler, J. E. Birren, S. E. StumpfOral aspects of aging: R. F. Sognnaes, A. A. Dahlberg,

J. Nalbandian, J. Klingberg, L. Cancellaro, E. 0.Butcher, J. R. Ring

Financing medical costs after age 65: J. T. FreemanDiscussions. Ilndex

British agents: Bailey Bros. & Swinfen, Ltd.Hyde House, West Central StreetLondon W.C.1

American Association for theAdvancement of Science

1515 Massachusetts Ave., NWWashington 5, D.C.

I

776