824 THE JOURNAL OF BOTANY 
When a book has reached such a standing, it is generally ss 
to let well alone. But we have — an exception here. 
—— —— the fortunate idea of expanding the third edition 
e it a text-book of plant diseases. The number of 
illustrations i is bse and the additions to the text are of course 
numerous. nnot help in some cases feeling that some = 
these siiditiona: aie: been made in a perfunctory way. I find n 
intrinsic fault, least of all in a German book, = their sientfibbe 
sani especially when accompanied by many good figures. 
But — with the original Fortine the additions are 
cacdaially. 10 eagre. For example, a page and a half on the 
potato disease a: reg is not much, ‘ais tee is no 
figure of this @ of 3 a most valuable crop, while on the next page 
S 
far from it: it is ood—but sabi books of plant diseases addressed 
to ell as 
should recognize the practical side of things, as this book so 
expressly did in its former editions. My point is therefore that, 
though expanded, and expanded well, it is be expanded enough. 
I trust that sickas ten years will not be required before we have 
a fourth edition in which expansion will be carried to symmetrical 
proportions. 
ould be ungracious to part from so much that is good, 
admirable, and useful in a growling spirit. I do not complain so 
much as I ask for more from the same source. Prof. Hartig is 
far above criticism as an — of plant diseases —but I venture 
to think he could do better as the writer of a book, if he would give 
us more, rather than sas ots of the stores of his experience. 
The Physiology of Plants. A Treatise upon Metabolism and Sources 
of Energy in Plants. EFFER. Second edition. 
—— and edited by Arrep J. aie D.Sce., &c. Vol. i. 
Large 8vo, pp. xii, 682, with 70 kg in ae text. Oxford : 
Olarendde Press. 1900. Price 
Tue translation of Pfeffer’s Morea of Plants is a welcome 
addition to the familiar Clarendon Press series of botanical text- 
literature brings the volume as well up to date as we can expect in 
a general treatise. The term Physiology is used in its more restricted 
sense, and the present volume, as explained in the title, covers only 
a portion of the = namely, the fundamental principles of meta- 
bolism and the sources of energy, or, impler language, the 
building > and breaking down processes eae | with nance 
and the supply of energy. The ways which this energy 1 
expended, din the most nbrilcings tetera of the plant as 
