260 
Review. 
the other chief groups of the plant kingdom in descending order , 
finishing up with the bacteria. The book closes with two chapters, 
on “Sex and Heredity ” and on “Alternation of Generations, and 
the Land Habit,” and with two appendices on “ Types of Floral 
Construction in Angiosperms ” and on “ Vegetable Food-Stuff’s.” 
The justification of the progress in description from the complex to 
the simple which the author hopes will be found “ in the accessory 
and in the employment of materials later in the book” is not very 
obvious to the reader. The advantage of first describing and 
analysing the structure and functions of the complex seed plant, 
which is the type most familiar to the layman, and from the study 
of which many different kinds of everyday facts can be readily 
explained, has been very generally recognised ; but once this has 
been done it is difficult for most lecturers and writers to resist the 
appeal of gradual progress from the simpler to the more complex 
and from aquatic to subaerial life. Nor are the positive advantages 
of the descending order quite clear. We presume the author finds 
them in the facility of immediate comparison of each group with a 
preceding one, beginning with a comparison of Gymnosperms and 
Angiosperms. 
The space devoted to the different groups is not always in 
accord with their intrinsic importance in the scheme of plant life. 
Fourteen pages are devoted to Gymnosperms, thirty-seven to 
Pteridophytes, eighteen to Bryophytes, twenty-five to Algae and as 
many as fifty-nine to Fungi. We should have liked to see more 
space given to Algae, which are from so many points of view 
fundamental to an understanding of the higher plants. As Mr. 
Church has recently pointed out, 1 algae have always been rather 
scandalously neglected by the land botanist: yet among them we 
learn facts of cell structure and reaction, of tissue arrangement and 
reproductive mechanism, without a knowledge of which we cannot 
hope to understand the original equipment which the landward 
migrants had at their disposal to meet the special problems of 
subaerial life. The Bacteria only get three pages of Professor 
Bower’s book, a space which is quite inadequate to do the slender¬ 
est justice to their enormous interest and importance in the world. 
It is most desirable that the medical student, especially, should have 
his attention directed to this group hy a biologist, who is or should 
be able to give the beginner some vivid and comprehensive idea of 
the stupendous and varied parts bacteria play in the world, on 
their own account and in relation to other organisms, so that the 
student should not wait until he is compelled to view them, at a 
much later stage of his course, almost entirely as causative agents 
in disease. 
The two concluding general chapters deal with their respective 
subject in the light of modern knowledge, and they are decidedly 
harder reading than the body of the book. No attempt is made to 
deal with the process of evolution itself, except incidentally in the 
discussion of mutations. Though so little is actually known of the 
process of evolution it would seem desirable to have made a direct 
attempt to give the elementary student some idea of what is thought 
and held as to this process, and of the evidence on which current 
theories are based. 
1 Thalassiophyta and the Subaerial Transmigration, Oxtord Botanical Memoirs, 
1919. 
