December 22, 1916] 



SCIENCE 



895 



the disappearance of the compounds was chiefly 

 due to biological causes. 



From the bottles or pots three species of 

 bacteria were isolated, one of which uses pyri- 

 dine as a source of nitrogen, one vanillin as a 

 source of carbon and one cumarin as a source 

 of carbon. An organism acting on quinoline 

 has not yet been found. 



This would seem to show that the enormous 

 increase in numbers of organisms noted in 

 the treated pots and the disappearance of the 

 four substances in the soil depend on the fact 

 that they (the compounds) serve as food 

 sources to definite species of bacteria. 



The significance of these facts to the soil 

 toxin theory of soil fertility is evident. The 

 persistence of vanillin, for example, in some 

 soils and not in others may be due to the fact 

 that the vanillin organism is absent or to the 

 fact that conditions are not suitable for its 

 development or for the use of the vanillin. If 

 we should be able to improve a soil containing 

 vanillin by treating it with the vanillin organ- 

 ism the results should be a strong argument 

 for the soil-toxin theory of soil fertility. This 

 of course is a step into the future. 



The results are also suggestive in explaining 

 some of the phenomena accompanying "par- 

 tial sterilization." They would suggest that 

 in " partial sterilization " (at least that caused 

 by these four compounds) we do not have a 

 large increase in the numbers of microorgan- 

 isms because the less resistant are killed and 

 the resistant forms given opportunity to 

 develop; or because voracious protozoa are 

 eliminated; but because the sterilizing agent 

 used serves directly 6 as a food source. In the 

 case of steam, and perhaps carbon bisulphide, 

 unavailable food supplies are probably made 

 available. William J. Bobbins 



Department of Botany, 

 Alabama Polytechnic Institute, 

 Auburn, Alabama 



SOCIETIES AND ACADEMIES 



THE AMERICAN PHYSICAL SOCIETY 

 The eighty-fifth regular meeting of the Ameri- 

 can Physical Society was held in the Eyerson Lab- 



« This has been suggested for pyridine. See 

 Buddin, W., Jour. Agr. Sci., 6, 416-451 (1914). 



oratory of the University of Chicago on Saturday, 

 December 2. 



The following papers were presented: 



' ' On the Velocity of Sound in Metal Tubes, ' ' by 

 Karl K. Darrow, University of Chicago. 



"Collapse of Thin Tubes Shorter than the Crit- 

 ical Length, " by A. P. Carman, University of Illi- 

 nois. 



"An Acoustical Thermometer," by P. B. Wat- 

 son and H. T. Booth, University of Illinois. 



"A General Method of producing the Strobo- 

 seopic Effect, and its Application in the Tono- 

 deik, " by L. E. Dodd, State University of Iowa. 



' ' The Intensity-factor in Binaural Localization 

 and an Extension of Weber's Law," by G. W. 

 Stewart and O. Hovda, State University of Iowa. 



"An Apparatus for the Demonstration to an 

 Audience of Simple Harmonic Motion," by Paul 

 E. Klopsteg, University of Minnesota. 



"Eeport of Progress on the Measurement of 

 Earth Eigidity, " by A. A. Michelson and Henry 

 G. Gale, University of Chicago. 



' ' The Accuracy with which Gravity may be pre- 

 dicted at any Point in the United States," by 

 John P. Hayford, Northwestern University. 



"A Proposed New Method for the Determina- 

 tion of the Acceleration due to Gravity," by Her- 

 bert Bell, University of Michigan. 



"On Some Very Large Variations in the Ad- 

 sorption of certain specimens of Charcoal," by 

 Harvey B. Lemon, University of Chicago. 



' ' The Principle of Similitude, " by C. S. Frazel, 

 University of Illinois. 



"Preliminary Notes on the Torsional Elasticity 

 of Drawn Tungsten Wires," by L. P. Sieg, State 

 University of Iowa. 



"A Precision Calorimeter for measuring Heats 

 of Dilution," by D. A. Maclnnes and J. M. 

 Braham, University of Illinois. 



' ' Note on the Amount of Error in applying to 

 Non-Parallel Plates the Formula for Electrical 

 Capacity of Parallel Plates," by L. E. Dodd, 

 State University of Iowa. 



"The Kinetic Theory of Non-Spherical Eigid 

 Molecules," by Yoshio Ishida, University of Chi- 

 cago. 



' ' The Photo-electric Emission from Crystals of 

 Selenium," by P. C. Brown, State University of 

 Iowa. 



' ' The Production of Light by Cathode Bays in 

 Air," by Gordon S. Puleher, University of Wis- 

 consin. 



"The Optical Constants of Liquid Alloys," by 

 Carleton V. Kent, University of Michigan. 



"The Single-lined and the Many-lined Spec- 



