i 
Aprit 7, 1923] 





























wise the book would have become very unwieldy, but 
it has meant that a number of important papers pub- 
lished in German journals are not mentioned. For 
example, Dr. Bogue is a great advocate of the fibrillar 
structure of gels, but no mention is made of similar 
put forward by Moeller in a number of different 
papers in the Kolloid Zeitschrift. A lucid description 
is given of the various physico-chemical properties of 
gelatins and glues and the various theories are dealt 
in detail. If anything, the author has not been 
sufficiently critical in describing the theories of Brails- 
ford Robertson, who assumes a peculiar kind of dis- 
sociation which appeals neither to the organic nor to 
the physical chemist, and against which there is a mass 
of evidence accumulated by Pauli, Loeb, and others. 
Actually, Dr. Bogue attempts to modify Robertson’s 
theory, so as to make it more in accordance with the 
work of Loeb, but the modified theory is still open to 
most of the objections raised against the original 
theory. . 
The second part of the book deals with the techno- 
logical aspects of the manufacture, testing, chemical 
analysis, evaluation, uses and applications of gelatin 
and glue. The point of view taken is that of the chemist 
rather than that of the plant technologist, and this 
nakes the appeal of the book all the greater to the 
student and investigator. In the chapter on the uses 
and applications of glue there is a section on glue-room 
conomy and technology, which may be recommended 
r study to all users of glue on a large scale, so that 
ncreased efficacy, based on the application of scientific 
principles, may be attained in their workshops. 
There is also a special chapter on water-resistant 
glues and glues of marine origin, which should be read 
in conjunction with the first report of the Adhesives 
esearch Committee. An appendix deals more 
especially with the electrometric and indicator methods 
of determining hydrion concentrations. 
_ Generally speaking, there is little which calls for 
priticism, except the curious statement made on p. 
21 that acetic acid is an amphoteric substance be- 
cause the hydrogen of its carboxyl group may be sub- 
tituted by metals and the hydroxyl by chlorine (by 
the use of phosphorus trichloride). A few misprints, 
such as “existance” and “catinary,” have been 
noticed, and the following statement on p. 141 requires 
revision: “ but this does not follow for a continuous 
membrane that was semipermeable in the sense of 
being able to dissolve the solvent or medium of dis- 
persion would likewise behave as an _ ultra-filter.” 
Also, why should it be necessary to write “ Anfangs- 
dekrement ” instead of “ initial decrement ” ? 
; TD 79. 2. 
| No. 2788, voL. 111] 
NATURE 
_ This was probably a wise course to adopt, since other- | 
457 

Flora of New Zealand. 
Die Vegetation der Erde. Sammlung pflanzengeo- 
graphischer Monographien. Uerausgegeben von 
Prof. A. Engler und Prof. O. Drude. XIV. The 
Vegetation of New Zealand. By Dr. L. Cockayne. 
Pp. xxili+ 364+2 maps+65 plates. (Leipzig: W. 
Engelmann ; New York: G. E. Stechert and Co., 
1921.) 
ITH the landing of Sir Joseph Banks and Dr. 
Solander at Poverty Bay on October 8, 1769, 
our knowledge of the flora of New Zealand commenced, 
but unfortunately the results of the labours of these 
two intrepid explorers have never been published, 
though the plates of the new plants were prepared 
‘at Banks’s expense and the descriptions were drawn — 
up by Solander. From this time onwards various 
expeditions, both English and French, reached New 
Zealand, making small collections, the results of which 
were published, but Sir Joseph Hooker’s first volume 
of his “ Flora Antarctica,” published in 1847, must 
be regarded as the first comprehensive flora of these 
islands. As a result of the help received from many 
collectors, Hooker published his “Flora Novae 
Zelandiae” (1853-55), which truly marked a new era 
in the botany of New Zealand, but still little was 
known of the South Island alpine flora, and it is to 
Travers, Haast, Hector, and Buchanan that we owe a 
great deal of our knowledge of the flora of this region. 
Sir Joseph Hooker again contributed to our know- 
ledge of the flora in his “* Handbook of the New Zealand 
Flora ” (1864-67), undertaken at the instance of the 
Government of New Zealand, and since then the task 
has been fittingly and very ably taken up by New 
Zealand botanists, among whom must especially be 
mentioned T. Kirk, T. F. Cheeseman, D. Petrie, and 
L. Cockayne, the author of the valuable work under 
notice. Dr. Cockayne commenced his botanical work 
in 1887, and has continued his explorations with great 
assiduity and keen insight ever since. Becoming 
gradually more interested in ecology, the present 
volume, dealing with the vegetation of New Zealand 
in its many aspects and in relation to the varied plant 
associations, could not have been entrusted to more 
worthy hands. Nor could the subject have been more 
ably treated. 
In an introductory chapter the history of our know- 
ledge of the flora is detailed and the book is then 
divided up into four parts. The first part, as is proper 
in a treatise planned on ecological lines, deals with 
the physical geography and climate of the three main 
islands and of the outlying groups, the chapter on the 
climate and rainfall being contributed by Mr. D. C. 
Bates. It is unfortunate that the maps are sadly 
oO! 
