54 NATURAL SCIENCE [July 
the supply of which has always been abundant. But a growing need 
was felt for a general and elementary ‘Zoology’ written more par- 
ticularly so as to express the views of the majority of teachers in this 
country. The differences between the teaching and current doctrines 
in one country and those in another are not great, and perhaps not 
very important, yet they are distinctly appreciable. Mr Sedgwick 
has now brought out the text-book of general and systematic zoology 
of which the first volume is before us. In his preface the author 
tells us that it was his original intention to issue a revised edition of 
Claus’ well-known ‘Lehrbuch’; but that he changed his plan, and 
has written a book which is a new work although following the same 
lines as the older one. 
The present text-book is intended to help the student who has 
already acquired a preliminary knowledge of certain types of animal 
life, and wishes to proceed to a more thorough study of zoology. 
The whole work will probably be completed in two volumes. The first, 
with which we are now concerned, deals with the Phyla Protozoa, 
Porifera, Coelentera, Platyhelminthes, Nemertea, Nematelminthes, 
Rotifera, Mollusca, Annelida, Sipunculoidea, Priapuloidea, Phoronidea, 
Polyzoa, Brachiopoda, and Chaetognatha. The second volume will 
include the Arthropoda, Echinoderma, and Vertebrata, with general 
discussions of “the facts and principles of Zoology.” 
The work is distinguished by the clear and straightforward manner 
in which it is written ; whether we agree with the author or not, we 
never have any doubt as to his meaning. Superfluities are ngidly 
excluded, and by the judicious use of small type the bulk of the 
volume is kept within reasonable bounds. Throughout, the facts are 
treated in strictly systematic order, as many families are mentioned 
as possible, and a large number of genera are named. The book will, 
therefore, prove a very useful work of reference, in which both facts 
and names can be readily found—a task rendered easy by the help of 
an excellent index at the end of the volume. 
As we should expect from the pen of an author whose researches 
have extended over such a wide field, and whose experience in teach- 
ing is so great, this volume is well up to date, and singularly free from 
those blunders which so frequently disfigure text-books. This is no 
doubt partly due to the fact that Mr Sedgwick has often secured the 
help of specialists in reading over and correcting the proofs. 
Mr Sedgewick, as is well known, is an opponent of the ‘ cell-theory’ 
—accordingly in his general definitions he endeavours to avoid the 
use of its ‘language.’ For him, the Metazoa are merely multinuclear 
animals, “in which the nuclei are for the most part arranged regularly 
and with a definite relation to the functional tissues.” We must con- 
fess that this attempt to boycott the ‘cell-theory, which after all is 
merely a descriptive statement of perfectly obvious facts, tends to 
become somewhat pedantic, and moreover is futile, since again and 
again the writer is obliged to return to “the language of the cell- 
theory,” without which no description of Metazoan tissues can be 
intelligible or correct. If certain authors have erroneously taught 
that the cells of a tissue or embryo are entirely independent organisms, 
surely this is no reason why we should abandon the use of the term 
cell, any more than we should give up the words ‘segment’ or ‘meta- 
