252 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



in their natural habitat is just what is wanted by the cultivator in this 

 country. The thirty-nine articles or chapters are too numerous to give in 

 detail, but they cover the following and other subjects, viz. iris, alpine 

 plants, seeds, weeds, annuals, Primulas, insectivorous plants, roses, shrubs, 

 bulbs, sub-tropical plants, pruning, propagating, &c. We think there are 

 too many words printed in italics ; if confined to the names of plants the 

 work would have been improved, but as it is italics are freely used for all 

 sorts of words which the authoress desires to emphasize. However, this 

 may be a matter of taste ; many will no doubt approve of what we dis- 

 approve. 



"Intracellular Enzymes." By H. M. Vernon, M.A., M.D. 8vo., 

 240 pp. (Murray, London, 1908.) 7s. 6d. net. 



This work will appeal chiefly to those interested in the chemical side 

 of the physiology of animals and plants. The subject matter, however, is 

 of very great importance to all advanced students of biology and much 

 of the information has been collected in one volume for the first time. 

 The book is based on lectures given at the Physiological Laboratory of the 

 University of London. The author truly summarizes the importance of 

 the subject by stating that it " bids fair to become, if it has not already 

 become, one of the most important branches of biochemistry, for it alone 

 seems to offer a clue to the solution of the most fundamental of all 

 biological problems — the nature and constitution of protoplasm." 



Observations of enzyme activity have accumulated so rapidly during the 

 last few years that we are unable at present to clearly estimate the im- 

 portance of the results obtained. We " cannot see the wood for the trees." 

 This is no doubt the reason why Dr. Vernon has found it difficult to fit 

 together fragments collected with much industry from the scientific 

 journals of the world. Many of the results obtained by the original 

 workers are mutually contradictory, and many more are difficult to explain. 

 The author has endeavoured to deal critically with this mass of material, 

 and has accomplished his task fairly and judiciously. His own original 

 observations, which are many and important, receive the same impartial 

 treatment. It would, perhaps, have been convenient to busy workers if 

 the vegetable enzymes had been separated from the enzymes of the animal 

 world, but comparison between similar enzymes in the two kingdoms would 

 then have been made more difficult. At present, to quote but one instance, 

 the proteolytic enzymes of animals are much better understood than those 

 of plants, and any worker who wishes to deal with the proteases of plants 

 must first become acquainted with the work of animal physiologists. Dr. 

 Vernon has laid due stress on theoretical questions such as " the rate of 

 enzyme action," "reversible enzyme reactions," "the energy relations 

 of reacting systems," " the influence on reaction of temperature and of 

 the products of reaction," and he has emphasized the fact that enzymes 

 may, and often do, synthesize as well as decompose. They are factors 

 in anabolism as well as in katabolism. 



The student will find the book a mine of information, but he must 

 bo prepared to dig. It is not a volume of light literature for leisure 

 hours. Full references are given to all the most important original 

 papers. 



