Botany and Zoology. 317 



facts connected with the intrusion and method of occurrence of a 

 number of areas of igneous rocks, well known from the large 

 amount of geological literature bearing on them, such as the 

 Adamello and Riesenferner groups and Predazzo and Monzoni. 

 It contains a number of new facts and will prove of interest and 

 value to those whose studies lead them to look up the literature 

 dealing with the geology of these regions. — Tschermalc's Min. 

 Petr. Mitth,, xvii, 1897. " L. v. p. 



8. Petrology for Students, an introduction to the study of rocks 

 under the microscope ; by Alfred Harkee. Second ed., 12mo, 

 pp. 334 (University Press, Camb.). — We have had occasion to notice 

 previously the appearance of this excellent little manual. The 

 fact that it has now run into a second edition shows that it was 

 needed. The new edition, in addition to a thorough revision, con- 

 tains some new matter, especially references to American localities 

 and rock types, which will render it more useful in this country. 



l. v. p. 



III. Botany and Zoology. 



1. Pflanzen physiologic Ein Handbuch der Lehre vom Stoff- 

 wechsel und Jtraftwechsel in der Pflanze / von Dr. W. Pfeffer, 

 Professor an der Universitat Leipzig. Erster Band. IStoffwechsel. 

 Leipzig, 1897. — This is the first volume of the revised edition of 

 a work which was issued in 1880, when its author was a professor 

 in Tubingen. During the period of almost twenty years which 

 have elapsed since the first date, Professor Pfeffer has continued 

 to enrich every department of vegetable physiology. His com- 

 munications have touched some fields which lie on the border 

 between physiology and other sciences, while in the domain of 

 physiology itself the contributions have been important and, in at 

 least one part, revolutionary in their effects. The peculiar rela- 

 tions of motile protoplasm to chemical agents and to tinctorial 

 reagents, have been made so clear that the work of further experi- 

 menting in this field promises substantial results. In other 

 branches of experimental morphology, also, Professor Pfeffer has 

 opened up new paths. 



For this revision students have been waiting with impatience. 

 Under the condition of extreme specialization which now prevails, 

 and which is likely hereafter to characterize all scientific research, 

 an occasional presentation of a balance sheet by a critical master 

 is an absolute necessity. It was expected that in this complete 

 revision would be given such a balance sheet, contrasting the 

 real contributions, however trivial, with the untrustworthy and 

 unverified results which clamor for publication. This hope has 

 not been disappointed. All questions have been discussed impar- 

 tially and decisions have been made without prejudice. There- 

 fore, as might be looked for, this treatise is a distinct contribution 

 in itself to the department of vegetable physiology. Professor 

 Pfeffer has always paid much attention to the dynamics of vegeta- 



