January 17, 1902.] 



SCIENCE. 



101 



color making tliem more readily intelligible, 

 and the German is everywhere easy of com- 

 prehension. 



In general terms we can say of this part, as 

 of those which have previously appeared, that 

 it maintains the highest standard of descrip- 

 tive anatomical work, and when the treatise is 

 completed we shall have in accessible form de- 

 tails of the structure of the frog only exceeded 

 in anatomical literature by those relating to 

 man. One can only wonder how a man, turn- 

 ing out so much research in other lines, can 

 find time to produce such a monumental work 

 as this. Not only has practically all of the ex- 

 isting literature been analyzed (the list of 

 papers relating to the viscera includes 877 ti- 

 tles, some of course duplicate), but every 

 point has been, as the title page says, 'neu 

 bearbitet.' It is not possible to hope for a 

 translation of such an extensive work, but the 

 original must have a place in every biological 

 laboratory in the country. 



J. S. KlNGSLEY. 



A Laboratory Guide to the Study of Qualita- 

 tive Analysis. By E. H. S. Bailey, Ph.D., 

 Professor of Chemistry, and Hamilton P. 

 Cady, A.B., Assistant Professor of Chem- 

 istry in the University of Kansas. Fourth 

 edition. Philadelphia, P. Blakiston's Son 

 & Co. 1901. 



In the preface to this edition the authors 

 say, "At the present time there seems to be 

 an opportunity to broaden the methods of 

 instruction in qualitative analytical chem- 

 istry, and to teach not only the facts and the 

 mechanical methods of carrying out the vari- 

 ous operations of analysis, but also to render 

 them more intelligible and interesting to the 

 student by a proper application of the theory 

 of electrolytic dissociation and of the mass 

 law. * * * The aim of the authors has been 

 to produce a book which would enable the 

 careful student to successfully carry on the 

 work without the constant assistance of the 

 instructor." 



Several of the current manuals in their 

 latest editions open with an introduction 

 pointing out the significance of these theories 

 for analysis, and in some the dissociation of 



the text has begun, as evinced by the furtive 

 appearance of ions here and there throughout 

 their pages. 



The present authors are thorough; their in- 

 troduction of twenty pages explains the theory 

 of dissociation and the mass law, and the en- 

 tire book is written in terms of ions; for ex- 

 ample, "Antimony forms the positive antimo- 

 nous Sb*"^* ion, and the negative antimonite 

 SbOj , this antimonite, SbS^ , ortlio- 

 antimonate, SbO^ , this antimonate SbS^ , 

 and antimonyl tartrate, SbOC^H^Oj" ions." 

 Instead of acid or metal groups, we find 

 groups of anions and cations. 



The serious question is — are the operations 

 of qualitative analysis rendered more intelli- 

 gible to the student by this method? It seems 

 to the reviewer that they are made more in- 

 telligible to an advanced student, but less in- 

 telligible to a beginner; but the authors intend 

 this book for beginners. 



Por example the application of the phe- 

 nomena of hydrolysis of salts of weak acids to 

 the reactions occurring in the precipitation of 

 basic salts is doubtless a help to a riper stu- 

 dent. Again, while the following explanation 

 of another reaction might be clear to an older 

 student, might it not confuse a beginner ? " If 

 to a solution containing magnesium as ion, a 

 solution containing hydroxyl ions in consider- 

 able concentration be added, a precipitate of 

 magnesium hydroxid Mg(OH).„ is produced. 

 Ammonium hydroxid is a much weaker base 

 than magnesium hydroxid, and consequently 

 if an ammonium salt, such as ammonium chlo- 

 rid, be added, to a solution containing magne- 

 sium hydroxid, the hydroxyl ions from the 

 latter will combine with the ammonium ions 

 to form the slightly dissociated ammonium hy- 

 droxid, thereby decreasing the amount of the 

 magnesium hydroxid in solution. Therefore 

 the precipitate of magnesium hydroxid is 

 readily dissolved on the addition of ammonium 

 salts." 



In connection with the clause quoted, it 

 may be noted that in the separation of the 

 groups Al, Cr, Pe— Co, Ni, Mn, Zn— Ba, Sr, 

 Ca — Mg, the authors give directions with 

 each group to add ammonium chloride if it 

 is not already present, but give no reason for 



