168 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The student of chemistry, for whose special benefit these essays 

 are written, will find that the essentials of much of the enormous 

 amount of work which has been done within the past twenty years 

 has been systematized and digested for him, so that he may be saved 

 m.uch labour in searching for information, and may have expert 

 guidance as to what is likely to prove of value. There is little doubt 

 but that the purpose, tlie success of which Sir William Eamsay antici- 

 pates (in his preface to the volume) will be fulfilled — -namely, that the 

 essays will prove of use in suggesting lines along which valuable rather 

 than aimless research may be carried out. 



With regard to treatment, many of the chapters, from the very 

 nature of the work dealt with, can only appeal to students of chemistry, 

 and the handling of these subjects is quite justified by this assumption. 

 A few chapters — one especially dealing with recent attempts to " fix " 

 the atmospheric nitrogen by a practicable method, and so make ft 

 available in the form of artificial manures — should prove of great 

 interest to the horticulturist. The most involved chapter is probably 

 that dealing with the cohaltamines, and, though rival theories are dealt 

 with in all fairness and with but a reasonable amount of bias, it must 

 be confessed that Dr. Stewart has not succeeded in making this essay 

 very readable. This criticism, however, cannot be applied to any other 

 portion of the work, which generally is most lucidly treated. 



In such a volume as this one would expect to find some account of 

 radio-activity and radio-active substances. These subjects are, indeed, 

 dealt with, and in such a manner that, not only the student, but the 

 reader with a fair knowledge of chemistry and physics can profit by 

 a perusal of this part of the work. The author has confined his atten- 

 tion here to fact rather than theory, recognizing that the subject is 

 still in its infancy, and that such explanations as are generally given 

 are to be regarded as purely tentative. 



"Plant Galls of Great Britain." By E. T. Oonnold, F.Z.S., 

 F.E.S. 8vD., xh. + 292 pp. (Adlard, London, 1909.) Ss. 6d. net. 



The author has given us two other books on British galls, and in 

 the present one has combined much of the information contained in 

 the other two. The great majority of the curious growths occurring 

 on plants in Great Britain due to the punctures of insects or the attack 

 of fungi are described and in most cases figured. The galls are arranged 

 under the plants they attack, the latter being in alphabetical order. 



Here and there we think the author is mistaken as to the origin 

 of the gall, and in a few cases the " common " name of the plant is not 

 v/idely used — e.g. Lathyrus pratensis is here called wild pea but 

 the book will prove very useful and interesting to the field naturalist. 



It is rather a pity the autlior did not endeavour to make the 

 list complete and use others' observations more liberally. The definition 

 of " cambium " on p. 32 is out of date, and some of the names of 

 fungi are inaccurate — e.g. Puccinia fahae should be Uromyces fahae. 



