128 BIOLOGY AND ZOOLOGY 



In connection with the well-known method for estimating sulphates by precipitation 

 with barium chloride a recent thorough investigation (Allen and Johnstone, /. Amer. 

 Chem. Soc., 1910, 32, 588) has shown that the barium sulphate precipitate as usually 

 obtained is contaminated with alkali sulphate and barium chloride. The authors show 

 how the errors can be reduced to negligible proportions. 



For the rapid estimation of metals by electrolytic deposition it is advisable to keep 

 the electrolyte stirred and many workers advocate rotating the electrodes for this 

 purpose (see Price and Humphreys, J. Chem. Soc. Ind., 1909, 28, 117). Others maintain 

 that it is sufficient to pass a current of hydrogen or to work under reduced pressure; 

 in the latter case, the gas evolved from the electrolyte occupies a much larger volume 

 and effects thorough mixing (Fisher, Thiele and Stecher, Zeitsch. Elektrochem., 1911, 



17, 90S)- 



In connection with volumetric analysis attention may be drawn to the use of titanium 

 trichloride as a reducing agent (New Reduction Methods in Volumetric Analysis, 1910, 

 by Knecht and Hibbert). It may be used, for instance, in the estimation of iron, copper, 

 tin, hydrogen peroxide, chlorates, organic nitro-derivatives, methylene blue and indigo. 

 A useful paper has appeared recently in which the use of phenol phthalein as an indicator 

 is discussed, more especially in connection with its sensitiveness to carbon dioxide 

 (McBain, /. Chem. Soc., 1912, 101, 814). 



The methods of gas analysis have been extended by the application of refrigerants 

 for the purpose of fractional separation (Erdmann and Stoltzenberg, Ber.* 1910, 43, 1702, 

 1708). This procedure has been followed with very satisfactory results in the analysis 

 of mixtures of ethylene and hydrogen, ethylene and oxygen, carbon dioxide and oxygen, 

 nitrous oxide and oxygen. Attention may be drawn also to a valuable critical survey 

 of modern methods for estimating carbon dioxide, moisture, methane or other com- 

 bustible gas, and oxygen in air (Butterfield, Analyst, 1909, 34, 257). 



Among recent books or new editions of old books, of special value to chemical studentsi 

 the following may be noted: T. P. Hilditch, A Concise History of Chemistry; S. Arrhenius, 

 Theories of Chemistry; W. Ostwald, Outlines of General Chemistry (new edition); Sir W. 

 Ramsay's Textbooks of Physical Chemistry; J. C. Philip, Physical Chemistry and its Bearing 

 on Biology; Wo. Ostwald, Grundriss der Kolloidchemie; J. VV. Mellor, Modern Inorganic 

 Chemistry; A. F. Holleman, Textbook of Organic Chemistry (3rd English edition); N. V. Sidg- 

 wick, The Organic Chemistry of Nitrogen; A. H. Allen, Commercial Organic Analysis (4th 

 edition); Sir E. Thorpe's Dictionary of Applied Chemistry (new edition); Annual Tables of 

 Physical and Chemical Constants. (JAMES C. PHILIP.) 



BIOLOGY AND ZOOLOGY 1 



Biology and zoology are, fortunately, not like contemporary history; it seldom 

 happens that a new discovery, like a new historical event, completely overthrows 

 old land-marks, or transforms an account that is a year old to a halting record of knowl- 

 edge. There is a vast annual output of new work with which the specialist must keep 

 pace, each in his own branch, but the advance of knowledge is usually a slow progres- 

 sion, and it is even an advantage if general accounts, intended in the first place for 

 those who are not working specialists, are a trifle belated, for there has been time for 

 the new facts to lose some of their glamour of novelty and to fit into their appropriate 

 and usually rather inconspicuous places. 



How great is the actual output of newly published work, is not easy to realise. The 

 annual volumes of the Zoological Record, published by the Zoological Society of London 

 and by the International Catalogue of Scientific Literature, give only the titles of new 

 memoirs and the barest indices of their contents, and yet each volume contains on 

 an average about 1,200 closely printed pages. The Zoological Station at Naples 

 issues each year a volume (Zoologischcr Jahrcsbericht) intended to be a summary of 

 the more important results of the period dealt with, selecting points of anatomical 

 and morphological rather than purely systematic interest, and each of these reaches 

 between six and seven hundred pages. A brigade of specialists is employed on the 



1 See list of E. B. articles in Index Volume, pp. 889, 890, 891. 



