134 NATURAL SCIENCE [aneae 
structure, biological peculharities, 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 zUR 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. 
Pror. Mosius has here brought together the matter contained in 
several essays previously published in the Biologische Centralblatt (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 consequences 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 HIS BALLooN. By Henri Lachambre and Alexis Machuron. 8vo, viii+ 
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 Andrée’s balloon. Whatever geographical results we may learn 
from Andrée when he returns in the autumn, as there are still good 
erounds for hoping that he will, his expedition has already done 
valuable service by its contributions to aeronautics. Andrée, as an 
