A SPECTROPHOTOMETRIC STUDY OF THE "SALT 

 EFFECTS" OF PHOSPHATES UPON THE COLOR OF 

 PHENOLSULFONPHTHALEIN SALTS AND SOME BIO- 

 LOGICAL APPLICATIONS 1 



CHARLES L. BRIGHTMAN, M. R. MEACHEM and S. F. ACREE 



Contribution from the New York State College of Forestry and Syracuse 



University 



Received for publication, November 15, 1919. 

 INTRODUCTION 



This study was undertaken in connection with the investiga- 

 tion of the physiological, physical and chemical factors governing 

 the growth of fungi and bacteria on culture media, trees, pulp 

 wood, lumber, wood pulp and other cellulosic materials. In order 

 to study the nature and habits of the fungi and bacteria causing 

 the decay of wood and pulp and to devise and put into applica- 

 tion methods of control, it is necessary to have accurate data on 

 each organism concerned. Not only must the organisms be 

 identified in pure cultures, but the maximum, optimum and 

 minimum values of each essential physical, chemical and phys- 

 iological factor must be established. For example, each 

 organism living on an aqueous medium, and therefore in con- 

 tact with hydrogen and hydroxylions (and other chemicals), 

 will die if the concentration of the hydrogen ions (or other chemi- 

 cals) is too large or too small, and will have its optimum growth 

 when the hydrogen ion concentration is somewhere between the 

 maximum and minimum values of tolerance, this statement, of 

 course, presupposing that all other essential factors are constant 



1 This article is one that we are publishing in cooperation with Dr. Haven 

 Metcalf, in charge of Forest Pathology, Bureau of Plant Industry, Department 

 of Agriculture, on the quantitative studies of the various physical and chemical 

 factors governing the growth of fungi and bacteria on culture media and cellulosic 

 materials. 



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