Mat 26, 1916] 



SCIENCE 



747 



colloidal chemistry, i. e., the questions of sur- 

 face tension, adsorption, etc., which are of 

 such fundamental importance to the whole 

 subject, are first discussed toward the end of 

 the book. In the opinion of the reviewer this 

 is an unfortunate arrangement, for to take one 

 example, a treatment of the coagulation of 

 colloidal solutions without a knowledge of the 

 adsorption laws, must necessarily be handi- 

 capped to say the least. 



For the professional worker in the field of 

 colloidal chemistry, the book has little to offer, 

 first because of its brevity and second because 

 of the fact that although dated January, 1915, 

 many of the results of recent research are not 

 to be found in the book. 



However if one is interested in obtaining a 

 statement of the principal facts of colloidal 

 chemistry unenctunbered with too much 

 theory, the book is to be recommended. 



Walter A. Patrick 



HandhooJc of Colloidal Chemistry. By Wo. 



OsTWALD. Translated by M. H. Tischer. 



278 pp. Blakiston's Son & Co. $3.00 net. 



The above book is a translation of the third 

 German edition of Wo. Ostwald's " Grundriss 

 der Kolloidchemie." Wo. Ostwald's name has 

 been so intimately associated with the devel- 

 opment of colloidal chemistry, that it needs 

 no introduction even to American readers. 

 His broad general knowledge of his subject 

 reminds one very forcibly of the attitude of 

 his father, Wilhelm Ostwald, toward physical 

 chemistry. Following the footsteps of his 

 father, the son also endeavored to vrrite an 

 authoritative text-book in his own chosen 

 field. The above book is the result, and while 

 the reviewer can not agree with the translator 

 in saying that Wo. Ostwald in colloidal chem- 

 istry occupies a position analogous to Wilhelm 

 Ostwald in physical chemistry, or J. Liebig in 

 agricultural chemistry, nevertheless one must 

 agree that his text-book is most stimulating 

 and interesting. 



The book is divided into two parts, a general 

 and special study of colloidal chemistry. The 

 first part is devoted largely to classification and 

 systematics, being the particular field in which 

 Ostwald excels. . The treatment is very general. 



indeed in many cases it seems as if the spirit 

 of generalization was carried too far. This is 

 well illustrated in Ostwald's "negative" sur- 

 face tension, the existence of which is not sup- 

 ported by experimental evidence and which 

 would indeed be contradictory to our funda- 

 mental ideas of surface tension. 



The second part of the book dealing with the 

 properties of colloidal solutions is the most 

 interesting. This is especially true of that 

 portion which treats of the viscosity of col- 

 loidal solutions. 



The book is made very attractive with its 

 abundant photographs and tables. On the 

 whole the translation is acceptable, but the 

 frequent use of the ugly word " dispersion- 

 means " in the place of dispersion mediima 

 strikes one as inexcusable. 



Walter A. Patrick 



The House Fly, Musca domestica Linn., its 

 Structure, Habits, Development, Relation to 

 Disease and Control. By C. Gordon 

 Hewitt. Cambridge: University Press. 

 The house fly has been an illustration of the 

 fact that it is concerning the most common 

 animals that we often know the least. Though 

 associated with man through all ages, and 

 doing him incalculable injury, this insect, 

 until recently, was either viewed with com- 

 plete indifference or rather with favor as a 

 paragon of industrj^. To any one who desires 

 to see how all of this has been changed and 

 how fully the menace which the house fly 

 forms to public health has been established, 

 the book by Dr. Hewitt is highly recom- 

 mended. It is not a popular treatise in the 

 usual sense but, as the author states in the 

 preface, it complements the work by Dr. L. O. 

 Howard, " The House Fly : Disease Carrier." 

 Although primarily intended for entomol- 

 ogists, sanitarians and physicians, it contains 

 much matter of general interest. 



The various parts of the book deal with the 

 structure and habits of the house fly, its 

 breeding habits, natural enemies, various 

 related species frequenting houses, relation to 

 disease and control. The strongest parts of 

 the book appear to be those dealing with the 

 anatomy and with the dissemination of dis- 



