740 



SCIENCE. 



[N. S. Vol. II. No. 48. 



The Jurassic fauna consists largely^of species 

 apparently peculiar to Mexico. It is character- 

 ized by numerous forms of Aucella and Peri- 

 sphinctes, about half of which are described as 

 new species. This paper, following so soon 

 after the discoveries of Diller and Hyatt in 

 California, is of much interest to American 

 geologists. 



The authors have been unfortunate in the 

 hands of their lithographer. The plates are of 

 little use; some of the figures are scarcely rec- 

 ognizable. 



J. B. WOODWOBTH. 



An Introduction to General Biology. Sedgwick 



and Wilson. Second Edition. 1895. New 



York, Henry Holt & Co. 



The original Practical Biology of Huxley and 

 Martin, written in 1875, has stimulated the 

 production of a large growth of text-books and 

 laboratory manuals. Huxley and Martin at- 

 tempted to present the fundamental facts of 

 biology to the student by the study of a series 

 of typical animals and plants, beginning with 

 the simplest and ending with the more complex. 

 Nevertheless, this logical method proved im- 

 practical and in a later and too-much enlarged 

 edition the authors (or rather their successors, 

 with Huxley's approval) reversed the order of 

 treatment of the subject. The higher forms 

 were first studied and then the student was 

 led down through a series of simpler forms. 

 Huxley said, however admirable the] first 

 method followed by him had been ' it had its 

 defects in practice.' 



Sedgwick and Wilson adopted, in 1886, a third 

 order of procedure in the first edition of their 

 General Biology. Two common forms, the 

 fern and the earthworm, were first thoroughly 

 described as introductory to a later study of 

 other animals and plants; and a second volume 

 was prdmised, dealing with the other forms. 

 This second part has never appeared and its 

 publication has been finally abandoned. 



A second edition of the General Biology of 

 Sedgwick and Wilson has just come out and 

 will be welcomed by all those who have learned 

 through experience the great value of the first 

 edition. 



In the present edition the principal changes 



are as follows : (1) The book has been enlarged 

 so as to include a series of unicellular forms 

 (Amoeba, Infusoria, Protococcus, Yeasts, Bac- 

 teria). (2) The laboratory directions given in 

 the first edition have been omitted. In their 

 place an admirable appendix has been added. 

 The appendix describes the best methods in 

 preserving and preparing the forms described in 

 the text; a large number of valuable and prac- 

 tical suggestions are also added. (3) The order 

 of presentation has been reversed. The earth- 

 worm now comes first and then the fern follows. 



In the first edition, and in the present edition 

 also, the student is introduced to the subject of 

 General Biology by a chapter dealing with the 

 differences between living and lifeless things, 

 'believing that Biology should follow the ex- 

 ample of Physics and Chemistry in discussing 

 at the outset the fundamental jDroperties of 

 matter and energy. ' If we consider, however, 

 the unsettled state of mind of biologists at pres- 

 ent on these fundamental questions and, further, 

 the presumed ignorance of the student of all 

 knowledge of living things we cannot but think 

 this method of presentation open to question. 



The next two chapters in the present edition, 

 following the order of the first edition, deal 

 with a study of a series of heterogeneous objects 

 illustrating ' the structure of living things ' and 

 'protoplasm and the cell.' The piece de re- 

 sistance is then introduced. 



The reason assigned by the authors for offer- 

 ing first the earthworm ' lies in the greater ease 

 with which the physiology of an animal can be 

 approached.' However true this may be from 

 the student's standpoint, it presents ceftain 

 difiiculties to the concientious teacher, for in 

 i-eality very little physiology is actually known 

 for the earthworm, ' save by analogy with higher 

 animals. ' 



For ourselves, we prefer at present the old 

 sequence with the plant first and the animal 

 later, admitting wide scope for individual taste. 

 Practically, we have found that the new edition 

 adapts itself to our own idicsyncrasies and 

 works backward just as well as forward. 



Most important additions and corrections 

 have been made to .the description of the struc- 

 ture of the earthworm. The accounts of the 

 circulatory and nephrideal systems have been 



