CURRENT LITERATURE 
BOOK REVIEWS 
raheem ion dy csemproeie 
Hyd ion det i nd importance 
to investigators i in physiological and nee fields of a Two methods of 
making such determinations are more or less widely known and well standard- 
ized: the electrometric and colorimetric methods. Both the history of the 
development and accounts of the practical operation of making such determi- 
nations have heretofore existed in scattered periodicals, and a student desiring 
to follow one of the methods had the choice of searching through several 
periodicals for the necessary information or of consulting such works as 
Micwaetts.t A book by CLark? has recently appeared which will be welcomed 
by students of hydrogen ion concentration, both on account of its detailed 
information and authoritative nature, written as it is by one who has made 
many contributions toward the development of methods for a 
of this sort. Chapter i deals with “General relations among acids and bases 
then follow 59 pages on the colorimetric determination of hydrogen ion, sist 
pages on electrometric measurements, a short chapter of 5 pages on “Supple- 
mentary methods,” and lastly a chapter of 29 pages on “‘Applications.’”’ The 
book also includes a very complete bibliography and an appendix containing 
tables for converting Py to hydrogen ion concentration, other tables applicable 
to Py measurements, and a list of representative potentiometer equipment. 
nder ‘‘General relations among acids and bases” the author discusses 
the theory of dissociation in solution, and develops the related equations. The 
following 59 pages on colorimetric determinations include a chapter on the 
general method, two chapters on the theory and choice of indicators, another 
chapter devoted to buffer solutions, and two chapters concerning errors of 
the method and practical determinations with indicators. The author includes 
tables showing Sorensen’s indicators, Clark and Lubs series, and Gillespie’s 
x ge series, giving their Py ranges and other data necessary in using 
The section dealing with electrometric measurements is divided into 
= chapters. They include a short outline of the method, the theory of the 
hydrogen electrode, discussion and illustration of various types of electrode 
vessels, potentiometers and other electrical apparatus, hydrogen generators 
* MICHAELIS, LEoNoR, Die Wasserstoffionenkonzentration. Berlin: Julius 
Springer Co, 1914 
? CLARK, W. MAnsriexp, The determination of hydrogen ions. pp. 317. Balti- 
more: Williams & Wilkins Co. 1920 
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