NewBooksofInterestMar"h 24, 1950, Vol. 111 15 THE FRANZ KYMO TIMER traces an imtroved time scale in atl improved manner, on kymograph charts, as shown below. Two scales are traced

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BOTANYAn Introduction to Plant Science. By W. W. ROBBINS and T. E. WEIER,both at the University of California. Covers the basic facts of plant science andtheir relation to agriculture, medicine, and many other fields. The authors reviewrecent discoveries in plant anatomy, photosynthesis, respiration, genetics, waterrelations, growth substances, chromosome structure, and many other subjects.Ready in April. 479 pages. 490 illus. Prob. $5.00.

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SCIENCE March 24, 1950, Vol. 111

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PHYSICALScientific Foundations of Vacuum Technique. By Saul Dushman. 1949. 852 pages. 328 illus.$1 5.00.

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ORGANICOrganic Reactions. Volume V. Editor-in-Chief: Roger Adams. 1949. 446 pages. $6.00.

Isotopic Carbon. Techniques in Its Measurement and Chemical Manipulation. By Melvin Calvin,Charles Heidelberger, James C. Reid, Bert M. Tolbert, and Peter E. Yankwich. 1949. 376 pages.115 illus. $5.50.

The Chemistry of Organic Medicinal Products. Third Edition. By Glenn L. Jenkins and Walter H.Hartung. 1949. 745 pages. Illus. $7.50.

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A Brief Course in Organic Chemistry. First Edition, Revised. By Reynold C. Fuson, Ralph Connor,Charles C. Price, and Harold R. Snyder. 1947. 267 pages. Illus. $3.00.

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Organic Reactions. Volume III. Editor-in-Chief: Roger Adams.; 1946. 461 pages. $6.00.

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Introduction to the Chemistry of the Silicones. By Eugene G. Rochow. 1946. 137 pages. $2.75.

INORGANICBoron Trifluoride and Its Derivatives. By Harold Simmons Booth and Donald Ray Martin. 1949.315 pages. Illus. $5.00.

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M..trch. 24, 1950, Vol. 111 SCIENCE 19

SCIENCE March 24, 1950, VoL 111

REFLECTIONS OF'A PHYSICISTby P. W. BRIDGMAN

HIS COLLECTIONcomprises the bulk of

the non-technical writingsof Dr. Bridgman, togetherwith three papers here pub-lished for the first time.The topics range over aconsiderable field and may

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MAMMARY TUMORS IN MICEVIII+223 pages, 7% x 10%2 inches,double column, illustrated, clothbound

Reproduced, new price $3.50(to AAAS members $3.00)

This symposium volume of the AAAS has, dur-ing the five years since its publication, attracted in-creased attention. After having been reported outof print for some time, the volume is again available.It contains 12 papers, contributed by members ofthe National Cancer Institute.

* AAAS SYMPOSIUM and other PUBLICATIONS7Y2 x 10Y2 inches. illustrated, clothbound(a) indicates cash prices to members.(b) prices to nonmembers and institutions.

HUMAN MALARIA, 44 papers on history, parasitology,anopheline vectors, epidemiology, symptomatology, pathol-ogy and immunity, treatment, control and eradication;reprinted. 406 pp. (a) $4.00, (b) $5.00.

LIEBIG and AFTER LIEBIG-A Century of Progress inAgricultural Chemistry. 1t) papers make available in con-venient form the history of one of the most significant de-velopments in agricultural science. 119 pp. (a) $2.50,(b) $3.00.

] RELAPSING FEVER in the AMERICAS, 20 papers onsymptomatology, diagnosis, etiology, epidemiology, pathol-ogy and immunity, tick vectors treatment, and publichealth aspects. 136 pp. (a) $2.50, (b) $3.00.

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J DENTAL CARIES and FLUORINE, 11 papers report oninvestigations in the British Isles, India, South Africa andthe U.S.A. 111 pp. (a) $3.00, (b) $3.50.

Cl APPROACHES to TUMOR CHEMOTHERAPY, 41 papers.A progress report, addressed largely to future workers. 412pp. (a) $6.50, (b) $7.75.

RICKETTSIAL DISEASES of MAN, 27 papers record thecontrol of Rickettsial diseases during World War II andreveal the scientific foundation on which the adopted meti-ods rest. 255 pp. (a) $5.25, (b) $6.25.

C LIMNOLOGICAL ASPECTS of WATER SUPPLY andWASTE DISPOSAL (6 x 9), 8 papers sample the borderarea within the scope of interests common to the engineer,

the limnologist, and the oceanographer. 93 pp. (a) $2.75,fb) $3.25.

C AAAS PROCEEDINGS and DIRECTORY of MEMBERS1940-1948, 6 x 9 inches, 1219 pp.

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A.A.A.S. PUBLIC-ATMINS1515 Massachusetts Ave., N.W.Washington 5, D. C.Please accept my order for one copy of Mammary Tumorsin Mice and for the volumes checked above. My check inthe amount of $. .......... is enclosed.

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20 SCIENCE March 24, 1950, VoL 111

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