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, SCIENCE 



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A WEEKLY JOURNAL DEVOTED TO THE ADVANCEMENT OF SCIENCE, PUBLISH- 

 ING THE OFFICIAL NOTICES AND PROCEEDINGS OF THE AMERICAN 

 ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. 



NEW SERIES. VOLUME XXIII. 



JANUARY-JUNE, 1906. 



NEW YORK 



THE MACMILLAN COMPANY 



1906 



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