May 31, 1895.] 



SCIENCE. 



Gil 



the general purpose of the work, mucli 

 more space is devoted to the geographical 

 distribution aud general natural history 

 of mollusks than to the details of sj-stem- 

 atic arrangement or technical discussion. 

 Twelve chaptei-s of 377 pages are devoted 

 to generalities, and four, comprising (J6 

 pages, to classification. 



The work deserves high commendation 

 for the thorough manner in which Mr. 

 Cooke has foraged for fresh data, bringing 

 together a vast number of facts on the 

 biography, distribution, growth, anatomy 

 and reproduction of mollusks. The stj-le is 

 clear and easy, and the facts are well selected 

 and agreeably presented. For the audience 

 for which the book is intended it seems ad- 

 mu-ably adapted, and so far as we know 

 there is no work available at present which 

 can be more cordially recommended to a 

 beginner or the general reader. 



It would be easy to criticise details of 

 classification here and there, and on manj^ 

 points the opinions of experts will difler in 

 the present state of our knowledge ; but in 

 recognizing the aim of the author and pub- 

 lishers it must be conceded that it has been 

 well carried out. 



It does not appear to have been necessary 

 to separate the recent from the fossil bracli- 

 iopoda, and recent efibrts at a revised 

 classification of the group have been so 

 successful and complete that Mr. Reed's 

 work appears alreadj' somewhat antiquated 

 and too brief, but this perhaps was inevit- 

 able fi'om the necessity of preserving due 

 proportion between the parts of the series. 

 Mr. Shipley's account of the anatomy and 

 embryologj' is good, aud his conclusions as 

 to the relations of the class are conservative 

 and reasonable. 



The book is fiilly illustrated with rather 

 unequal woodcuts, many of which are good 

 and others rather ' wooden,' but an un- 

 usually large proportion of them are original 

 and fresh. There are four very good maps 



of geographical distribution and an excel- 

 lent index. W. H. Dall. 



A Laboratory Guide for a Twenty Weeks' Course 

 in. General Chemistry. By George W'il- 

 LARD Bextox, a. M., Instructor of Chem- 

 istrj-. High School, and Chemist for the 

 City of Indianapolis. Boston, D. C. Heath 

 &Co. 



This book might be better termed ' A 

 Guide for a Coui-se of Test-Tubing,' since 

 nearly all the reactions are performed in a 

 test-tube, and the sole object of the book 

 seems to be to acquaint the unfortunate pu- 

 pil who uses it with ' Tests ' for the various 

 elements and compounds. 



The manual is supposed to be put into 

 the hands of beginners in the subject, aud 

 yet before a single element is considered or 

 anything is said aliout elements, compounds 

 or formulas, quite a number of formulas and 

 reactions are given. As an illustration of 

 what the author calls compounds, a piece 

 of wood and granulated sugar are taken 

 and the equation C, jH, jO, . +HjS04 = 12C 

 + llHjO + H„SO^, is written out. Then 

 the student is asked to explain the equation 

 and to define a compound. And yet the 

 author, according to his preface, is one of 

 those ' who see in the Laboratory (with a 

 big L) the means of high development on 

 approved pedagogical grounds.' 



It would require more space than the 

 book is worth to point out all its faults. 

 It will, perhaps, be sufficient to st^ite that 

 directions are given for making dangerous 

 compounds ^\^thout any mention of the 

 danger connected with the work . The pu- 

 pil is a.sked, for example, to determine the 

 odor of carbon monoxide, and not an inti- 

 mation is given that it is one of the most 

 poisonous gases known to the chemist. 



Altogether, the book is one that can be 

 most cordially recommended as the kind of 

 a book for both teachers antl students to 

 avoid using, if possible. W . R . O. 



