452 SOME NEW BOOKS [DECEMBER 
power of reproducing vegetatively. Almost any portion of the plant will, under 
favourable conditions of moisture and temperature, give rise to a new individual, 
and there are alsoa great variety of means by which this can be naturally 
effected. It is this last aspect of their biology which forms the subject of Dr. 
Correns’ substantial contribution to Muscology, a work which we are sure will 
be perused with much interest by the increasing number of botanists who are 
specially interested in the Mosses. The book, which is partly special, partly 
general, opens with a short introduction (pp. xvii.—xxiv.), in which terms are 
explained and methods described. The ‘brood-organs” are in brief those 
organs which are definitely produced for the purpose of vegetative reproduction ; 
the “Stecklinge,” on the other hand, are those parts of the plant which will on 
separation form a new individual, but have not been definitely developed to 
that end. The greater part of the book (pp. 1-322) is “ special,” comprising 
first an account of the investigated cases of multiplication by “ brood-organs,” 
arranged systematically in tribes, families and genera, and secondly those 
species in which the other method obtains. This is followed by a “general” 
part (pp. 325-360), arranged in five sections, treating of the morphology and 
phylogeny, structure, development and germination, more especially of the 
“brood-organs,” and of their value for systematic purposes. A bibliography 
occupies a few pages, and the book closes with an index of the plants mentioned 
in the text. One cannot have too many illustrations in a work of this kind, 
and the 187 which are distributed through the text form a valuable help to 
the elucidation of the subject-matter. R. 
ANOTHER BOOK ON BACTERIA. 
Bacteria, especially as they are related to the Economy of Nature, to 
Industrial Processes, and to the Public Health. By Grorgk NEWMAN, 
M.D., F.R.S.E., D.P.H. (Camb.), ete., Demonstrator of Bacteriology 
to King’s College, London. Pp. viii. + 351, with 15 micro-photo- 
graphs by E. G. Spitta. London: John Murray, 1899. Price 6s. 
In his short preface the author expressly disclaims any attempt to write 
either a record of original work or a laboratory text-book. His object is merely 
to discuss in a popular scientific form the present state of knowledge concerning 
bacteria. As the title indicates, the bacteria considered are not only those 
capable of producing pathogenic effects, but include the vast number of those 
which are concerned in natural and industrial processes. 
Embracing so wide a range of subject, and being designedly written to 
suit the lay reader, the descriptions are unavoidably often sketchy and in- 
complete. But the author is in his happiest vein when dealing with the 
role of bacteria in natural processes, and with their industrial application, and 
to this the greater part of the book is devoted. The chapters on the bacteria 
in the soil, the bacteria of fermentation, and the bacteria of milk and its 
products, are specially valuable to medical readers for the lucid and interesting 
account they give of the far-reaching beneficial effects of bacteria. The 
ordinary student of medicine is too apt to associate bacteria with disease alone, 
and the author is to be congratulated on presenting in so attractive a form an 
outline of the immensely greater activities which these lower vegetable organisms 
possess. Whether the brief description of the chief pathogenic bacteria could 
be of equal value or interest to the lay reader, we are inclined to doubt, and 
it would be easy to criticise adversely some of the details given in this section. 
But the shortcomings of this latter part are only of minor importance, and 
do not detract from the value of the preceding chapters. 
The book is illustrated by several good illustrations from micro-photographs, 
and by a number of outline drawings of bacteria, for which the writer claims 
only a diagrammatic significance. It may be permitted to point out that some 
