January 27, 1950, Vol. 111 SCIENCE11

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12 SCIENCE January27,1950,Vol.111~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~-

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PROBLEMS of MORPHOGENESIS in CILIATESBy Andre Lwoff. The ways by which ciliates-non-cellular organisms-reconcile their non-cellular state with such processes as differentiation, development, morphogenesis, evolution, andreproduction, are considered in terms of particular phenomena in this new book. The subjectscovered include: the complicated life cycle of Gymnodinioides inkystans; aspects of the cineto-some; movements of the ciliary system in ontogeny and phylogeny; differentiation in ciliates;and interactions of morphogenetic units. A book in the WILEY BIOLOGICAL RESEARCH SERIES.Ready in April Approx. 80 pages 32 illus. Prob. $2.50

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January 27, 1950, Vol. 111 SCIENCE 17

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20 SCIENCE January 27, 1950, Vol. 111

LIMNOLOGICAL ASPECTS OFWATER SuPPLY AND WASTE DISPOSAL

v +87 pages-6 x 9-illustrated-clothbound- 7949 IaThis volume of 20 papers treats of a field of science of rapidly

increasing importance. In it engineering and limnology meet,and government plays an important role.

The papers in this new volume are not simply academic discussions of possibilities,but of sound biological and engineering science as applied to current practice innorthern Wisconsin and Minnesota. The 12 contributors to this volume are largelyfrom that area, but several are connected with institutions from Ohio to Boston.

PRICES FOR THIS BOOK IN CAR-TONS, postage prepaid, are as follows:Members of the bA^.A.A.S. .............$2.7S

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APPROACHES TO TUMOR CHEMOTHERAPYx + 42 pp.-7i x 10i--illustrated-clothbound-1947 I

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CITY .ZONE.STATE.

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20 SCIENCE January 27, 1950, Vol. 111

'LAB-AID" EXPEDITERS-they speed-up laboratory chores

7 CliCXfl paraffin knifemakes work with paraffin-embedded tissues quick andeasy. Great for cutting large blocks into small ones;for mounting blocks on a microtome object disc; forsquaring up blocks; for separating ribbons in a waterbath . . . Hollow stainless steel handle doesn't heat up;spring switch under thumb gives Finger-Tip Heat Con-trol -easy to keep knife at the right temperature.

C - DC When not in use lay knife in saddle rest- Blade UPkeeps knife hot; Blade DOWN current is "off."

1lChII1COII microslide dryerdelivers slides ready for staining in 7 minutes! Justdrop slides, in an Autotechnicon Slide Carrier, into thehatch, flip the switch and close the cover. A steadycurrent of warm, filtered air blowing over the slidescarries away all moisture, leaving them bone-dry anddust-free. The filter is replaceable. There's no distor-tion, either - the warm clean air is well below themelting point of paraffin.

water bathinsures smooth, even spreading of your tissue ribbons.The water temperature is just right- never too hot or

C!>2 too cold, thermostatically held at any set temperaturefrom 200 to 60TC. There's no melting paraffin to dis-tort tissues- no folds or wrinkles, no bubbles due tofrequent water change. Temperature stays constant,day-in, day-out. And it's easy to see your sectionsagainst the dull finished black interior of the bath.

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THE TECHNICON COMPANY215 East 149th Street, New York 51, N. Y.

Send me literature and prices on

W Technicon Paraffin Knife

X Technicon Microslide DryerL Technicon Constant Temperature Water Bath

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Deter~ma~tIom

Widespread acceptance of the Spencer Hb-Meter provesthat physicians need this means of obtaining laboratoryaccuracy in hemoglobin determination :n less than 3minutes.

Only the Hb-Meter permits:* Complete portability* Results in grams per 10Oml or a choice of

percentage scales* Hemolysis of blood without dilution* Accurate- determinations by persons with

deficient` color vision* Matching field within the spectral region

ofmaximum visual sensitivity

Ask your distributor to demonstrate the :Hb-Meter, or write Dept. A4.

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