634 



SCIENCE. 



[N. S. Vol. II. No. 45. 



near granite or gravels yielded by them are its 

 sources, whether it be in Cornwall, the Zinn- 

 wald, the Malay peninsula or Australia. The 

 large part played by tin in the bronze imple- 

 ments of the ancients and even in prehistoric 

 commerce give it peculiar claims to interest. 

 Enormous attention has been devoted to tin 

 mines in this country of late years, so much 

 that the metal has even been a political factor, 

 loudly heralded in recent campaigns. All our 

 enterprises have as yet been without success, 

 and some are instructive examples of extrava- 

 gant folly. Mr. Rolker's dispassionate and 

 truthful descriptions are timely and much to be 

 commended. 



J. F. Kemp. 



The Natural History of Plants, their Forms, 

 Growth, Reproduction and Distribution, from 

 the German of Anton Kerner von Marilaun. 

 By F. W. Oliver, with the assistance of 

 Marian Busk and Mary F. Ewart. With 

 about 1,000 original woodcut illustrations and 

 sixteen plates in colors. New York, Henry 

 Holt & Co. 1895. 2 vols., large 8vo. 

 This is a most interesting and readable book. 

 It is written in a clear and popular style ; few 

 technical terms are used, except where neces- 

 sary for the sake of accuracy, and the illustra- 

 tions are fine and full of interest. The whole 

 plan of the work is to treat plants as living 

 things and to find a biological significance for 

 all the parts of which a plant is formed. Here 

 will be found answered many of what may be 

 called the practical questions about plants ; 

 such as why certain species grow in peculiar 

 places, how they are adapted to the conditions 

 which surround them, how they get their food, 

 of what this food consists, how it is conducted 

 and formed into organic matter, and the struc- 

 tures and forms resulting. As the author says, 

 "For us no fact is without significance. Our 

 curiosity extends to the shape, size and direc- 

 tion of the roots, to the configuration, venation 

 and insertion of the leaves ; to the structure and 

 color of the flowers, and to the form of the fruit 

 and seeds ; and we assume that even each thorn, 

 prickle or hair has a definite ftinction to fulfil." 

 The author claims the advantageous aid of 

 imagination in his scientific researches and says 



that ' ' the more imagination an investigator has 

 the more keenly is he goaded to discovery by 

 this cra^^ng for an explanation of things and 

 for a solution of the mute riddle which is pre- 

 sented to us by the forms of plants." It is 

 probably due to this feature of the work that it 

 is so readable, and yet its scientific facts do not 

 suiFer on this account. The first four chapters 

 are devoted to the living principle in plants. 

 Protoplasts are considered as the seat of life; 

 the discovery of the cell and of protoplasm is 

 recounted with illustrations of both ; the move- 

 ments of protoplasts are illustrated from the 

 swarm spores of seaweeds, and the mosses and 

 ferns ; the movements of Volvocineas, Diatoma- 

 cese and Bacteria are described ; the continuity 

 of protoplasm through the cell walls and its re- 

 lation to vital force and sensation are explained. 



Under the heading of the Absorption of Nutri- 

 ment, inorganic and organic foods are treated, 

 the absorption of water and the character of 

 soils, as well as the symbiotic relations of 

 plants. 



One of the most interesting chapters discusses 

 the relations of the position of foliage leaves to 

 that of absorbent roots, proving that the leaves 

 conduct the rain to the point on the ground 

 where the roots of the plant can get it ; the 

 peripheral increase of the leaves keeping pace 

 with that of the roots. Most interesting dia- 

 grams are given of the position of leaves to fa- 

 cilitate this irrigation. In treating of Sapro- 

 phytes illustrations are dra'mi of those in water, 

 on the bark of trees and on rocks. Examples 

 are cited from the simplest as well as the most 

 highly organized plants, and many suggestions 

 are given as to the habitats of plants. 



The Absorption of Nutriment by parasitic 

 plants is described at length and illustrated by 

 numerous strange and unfamiliar examples. 

 Carnivorous plants also receive ample attention 

 and are illustrated by numerous cuts and a col- 

 ored plate. 



Under the heading of the Conduction of 

 Foods, the author treats of the regulation of 

 transpiration and the means by which leaves 

 are protected fi-om excessive drj^ness in exposed 

 localities. The diversity in the structure of 

 leaves is almost mai'velous, and the figures 

 given are of great variety and interest. In this 



