134 NATURAL SCIENCE [August 



structure, biological peculiarities, phylogenetic relations, and wide or 

 peculiar distribution." The descriptions are all in German, and 

 those of individual species are remarkably non-technical and lucid. 

 In each case the native habitat is given. The illustrations, which 

 are numbered to correspond with the species depicted, if not of a 

 very high order, are at any rate good enough to be an efficient 

 help in elucidating the text, and assisting in the determination of the 

 specific name. The book concludes with a good index. 



The Reproduction of Plants 



Beitrage zuk Lehre von der Fortpflanzung der Gewachse. By Prof. Dr M. 

 Mobius. 8vo, pp. viii., 212, with 36 figures in the text. Jena: Fischer, 1897. 

 Price, 4 Marks 50 pf. 



Prof. Mobius has here brought together the matter contained in 

 several essays previously published in the Biologische CentralUatt (1891, 

 1892, and 1896), which, with some additional chapters, make up a 

 useful and suggestive discussion of the methods of reproduction in 

 plants, both vegetative and sexual, the conditions on which they 

 depend, and the relations between the two kinds. There are five 

 chapters, namely : — 1. Introduction. 2. On the consecpLiences of con- 

 tinued vegetative multiplication of plants. 3. On the conditions that 

 govern the flowering of plants. 4 On the relation between spore and 

 bud formation in the reproduction of plants. 5. On the origin and 

 significance of sexual reproduction in the plant-world. In his introduc- 

 tion the author emphasises the contrast between the life of the indi- 

 vidual and the life of the species, as the key to the relation between 

 vegetative and spore reproduction, and indicates how the sexual process 

 may have arisen as a secondary result in the latter case. In the 

 second chapter a number of instances are adduced in support of the 

 contention that senile decay, as a result of continued asexual repro- 

 duction, exists " only in the imagination of certain authors and 

 breeders." Many cultivated plants, like the sugar-cane, have been 

 propagated from time immemorial only by the vegetative method ; 

 many, in fact, can be multiplied in no other way, and there is no 

 evidence to show that these are weaker or less healthy than the off- 

 spring of a sexual process. They have no predisposition to disease. 

 Epidemics are not peculiar to vegetatively propagated plants, but appear 

 even among wild plants, both annuals and perennials. An important 

 feature of the book as a whole is the great number of examples which 

 the author adduces in support of his contentions, rendering it useful 

 to the student quite apart from the intrinsic value of the conclusions 

 based thereon. 



The Makers of Andree's Balloon 



Andree and HI8 Balloon. By Henri Lachanibre and Alexis Machuron. 8vo, viii 4- 

 306 pp., coloured frontispiece, and 44 full-page illustrations. London : Constable 

 & Co., 1898. Price, 6s. 



The main interest of this work arises from its detailed description 

 of Andree's balloon. Whatever geographical results we may learn 

 from Andree when he returns in the autumn, as there are still good 

 grounds for hoping that he will, his expedition has already done 

 valuable service by its contributions to aeronautics. Andree, as an 



