Decembke 23, 1898.] 



SCIENCE. 



915 



until the second, and the problem of the rela- 

 tions of substance to substance, about which we 

 still know very little, is relegated to the third 

 and last division. 



The first part, or chemical dynamics, which 

 is now available in German and in French, 

 treats the subject under the two general heads 

 of Chemical Equilibrium and Reaction Velocity. 

 We have the physical and chemical equilibria in 

 a homogeneous substance, betvveen two sub- 

 stances, between three substances, between four 

 substances ; chemical equilibrium from the 

 moleeular-mechauical standpoint ; homogene- 

 ous and heterogeneous equilibra ; the law of 

 reaction velocity; reaction velocity and equi- 

 librium ; reaction velocity and affinity ; mono-, 

 bi- and tri-molecular reactions ; effect of the 

 surroundings and medium on reaction velocity; 

 effect of temperature ou the reaction velocity ; 

 effect of pressure on the reaction velocity. 



The translation of this, a part of Van't 

 Hoff's work, before the appearance of the re- 

 mainder, is indicative of that esteem in which 

 he is so justly held, not only at home, but in 

 foreign lands. The translation into French 

 seems to have been very carefully done, and 

 the French edition is an inviting one, barring 

 an occasional typographical error. 



It is a matter of delight to all who are inter- 

 ested in physical chemistry that books are 

 appearing simultaneously on the same chapter 

 of their subject, from the pens of two of the 

 great leaders in this field of work. As is well 

 known, that portion of Ostwald's Lehrbuch 

 which deals with the broad subject of Verwandt- 

 schaftslehre is now available in part. These 

 two works admirably illustrate the difference in 

 method of these two master minds, and each is 

 enhanced in value by the other. 



Haeby C. Jones. 



Laboratory Directions for Beginners in Bacteri- 

 ology. By Veeanus a. Mooee. 

 This book of ninety pages contains the out- 

 lines of an introductory laboratory course di- 

 vided into sixty lessons, and aims to impart a 

 technical and working knowledge of the more 

 essential bacteriological methods and to develop 

 a definite knowledge of a few important species 

 of bacteria. The book is not intended to re- 



place the text-book on bacteriology, but to be 

 a manual for use at the laboratory desk iu which 

 through a series of carefully selected exercises 

 the student, without waste of time, will cover 

 the necessary ground. 



A manual such as this represents strongly in 

 its selections and in the amount of time alotted 

 to each subject the personal opinions of Its 

 author, yet we believe on the whole the judg- 

 ment of the writer will be approved by teachers. 



This book will be found vei-y useful by teachers 

 who have not the time to prepare and print 

 their own outlines. Even those who are com- 

 pelled to give a course much shorter than that 

 sketched in this book can easily, without serious 

 harm, reduce the length of the course by omit- 

 ting the practical work in some of the chapters 

 and shortening it in others. The classification 

 of the bacteria upon the system of Migula seems 

 to us a mistake, for it necessitates many changes 

 in the accustomed nomenclature ; thus the 

 name bacillus is limited to motile rod-shaped 

 organisms to which the fiagella are attached to 

 all parts of the body. A bacillus with polar 

 fiagella becomes a pseudo-mouas and one with- 

 out any fiagella a. bacterium. As this book, is 

 intended to be used along with various text- 

 books on bacteriology, it would seem wiser to 

 have omitted any elaborate and unusual classi- 

 fication which, however valuable, must of neces- 

 sity frequently clash with that used in the text- 

 book, and thus tend to confuse the student. 

 Wm. H. Paek. 



GENERAL. 



The U. S. Department of Agriculture has 

 issued a bulletin on Fish as Food {Farmers^ 

 Bulletin, No. 85), by Dr. C. F. Langworthy, of 

 the Oflice of Experiment Stations, in which the 

 results of investigations on the nutritive value 

 of various kinds of sea food have been summed 

 up for the general reader. The chemical com- 

 position of a considerable number of fresh and 

 preserved fishes, moUusks, crustaceans, etc., 

 are given; the relative cost of protein and energy 

 in fish and other food material is shown ; the 

 place of fish in the diet is discussed, and some 

 sample menus are given to show how fish may 

 be combined with other food materials to make 

 a well-balanced dietary. The popular notion 



