518 



SCIENCE 



[N. S. Vol. LII. No. 1352 



The bottle and pipette were then filled with 

 the nutrient solution, care being taken that no 

 bubbles were inclosed beneath the stopper. 

 Loss in weight of the plant and container gave 

 the amount of transpiration, while the loss of 

 solution from the pipette gave the amount of 

 root absorption after temperature corrections 

 were made. These temperature corrections 

 were made by comparing these pipette read- 

 ings with those of a pipette in a similar bottle 

 containing no plant, but exposed to the same 

 set of conditions. Transpiration was measured 

 in grams while absorption was measured in 

 cubic centimeters, but as the variations in 

 density of the solutions for these temperature 

 ranges were small in comparison to the actual 

 values dealt with this correction was not made. 

 The experiment was performed on N^ovember 

 6, 1919, in the diffused light of the laboratory 

 during a period when variations in tempera- 

 ture and the index of evaporation were slight. 



TABLE I 



Data Showing Sates of Transpiration and Absorp- 

 tion of a Tomato Plant with Boots Immersed 

 Successively in a Three-salt Nutrient Solu- 

 tion of 1.75 Atmospheres Osmotic 

 Pressure, Cane Sugar Solution of 

 5.06 Atmospheres Osmotic 

 Pressure and Distilled 

 Water 



When the hourly rate of absorption is in ex- 

 cess of transpiration the ratio, A/T, is greater 

 than unity and the plant cells increase in 

 turgor. When this rate is less than unity 

 turgor is decreased and if the process is con- 

 tinued long enough the cells become flaccid 

 and the plant is seen to wilt. The plant gained 

 in turgor during the first two periods given in 

 Table I., but during the third and fourth 



periods the ratio values decreased very much. 

 This decrease was mainly due to lower absorp- 

 tion rates since the roots were surrounded by 

 a solution much stronger osmotically during 

 these two periods than during the first two. 

 The rates of absorption for the last two periods 

 were greatly increased by placing the roots in 

 distilled water. Earl S. Johnston 



Labokatokt of Plant Physiology, 

 Maryland Agricultural 

 Experiment Station 



THE AMERICAN MATHEMATICAL 

 SOCIETY 



The two hundred and twelfth regular meet- 

 ing of the society was held at Columbia Uni- 

 versity on Saturday, October 30, 1920, ex- 

 tending through the usual morning and 

 afternoon sessions. The attendance included 

 thirty-five members. President Morley occu- 

 pied the chair. The council announced the 

 election of the following persons to member- 

 ship in the society: Dr. P. M. Batchelder, 

 University of Texas; Miss Vevia Blair, 

 Horace Mann School; Mr. E. H. Carus, La 

 Salle, III; Mr. W. E. Cederberg, University 

 of Wisconsin; Mr. R. P. Conkling, Newark 

 Technical School; Mr. P. H. Evans, North- 

 western Mutual Life Insurance Company, 

 Milwaukee, Wis.; Mr. B. L. Falconer, U. S. 

 Civil Service Commission, Boston, Mass.; 

 Mr. J. A. Foberg, Crane Junior College, 

 Chicago, EL; Dr. Gladys E. C. Gibbens, Uni- 

 versity of Minnesota; Professor L. E. Gur- 

 ney. University of the Philippines; Professor 

 Archibald Henderson, University of North 

 Carolina; Miss Jewell C. Hughes, University 

 of Arkansas; Miss Claribel Kendall, Univer- 

 sity of Colorado; Mrs. M. I. Logsdon, Uni- 

 versity of Chicago; Mr. E. L. McNeal, Gen- 

 eral Motors Laboratories, Detroit, Mich.; 

 Mr. H. L. Olson, University of Michigan; 

 Professor Leigh Page, Tale University; Cap- 

 tain H. W. Eehm, Aberdeen Proving Ground, 

 Md. ; Mr. Ii-win Roman, Northwestern Uni- 

 versity; Mr. Raleigh Schorling, Lincoln 

 School, New York City; Mr. E. L. Thompson, 

 Junior College, Joliet, 111.; Dr. Bird M. 



