290 SOME NEW BOOKS [octobek 



FERMENTATION. 



The Soluble Ferments and Fermentation. By J. Reynolds Green, Sc.D., 

 F.R.S., Professor of Botany to the Pharmaceutical Society of Great 

 Britain. Pp. xiii. + 480. Cambridge University Press : C. J. Clay 

 and Sons, 1899. Price 12s. 



We can thoroughly recommend Prof. Reynolds Green's book to all who wish 

 to obtain a trustworthy guide to a correct knowledge of the processes of ferment- 

 ation. When we consider that it is little more than half a century since 

 Pasteur discovered that the cause of alcoholic fermentation is the activity of the 

 yeast plant, the strides made in our knowledge appear prodigious. There is 

 hardly any aspect of animal or vegetable life in which ferments do not play some 

 part. The ferments that cause our food to be digested, that produce clotting 

 of the blood, that bring about oxidation, that minister to plant life in various 

 ways, that are associated with the putrefactive and other changes wrought by 

 bacteria, are all described with full details, and in a lucid, interesting manner ; 

 the history of the subject is also well given. The distinction between the 

 organised ferments, like yeast and bacteria, and the soluble or unorganised 

 ferments or enzymes, such as pepsin of the gastric juice, and diastase in 

 germinating seeds, is a useful one. But the difference is more apparent than 

 real, for probably in all cases the micro-organisms which are called organised 

 ferments perform their work by secreting soluble ferments or enzymes. The 

 recent work of Buchner has certainly shown this to be the case for yeast. 

 What enzymes really are, and how they produce changes in large masses of 

 material without any apparent change in themselves, or in their power, are 

 much more difficult points to answer ; the reader will, however, find in this 

 book such general questions discussed in the light of recent knowledge. The 

 ferments themselves, so far as any positive statement can be made, appear to be 

 real chemical substances, and in their composition are allied to the albuminous 

 bodies, particularly to the class known as nucleo-proteids. The interesting 

 recent work of Emil Fischer, which is very clearly described, shows a possible 

 way in which such substances could produce the change known as fermentation. 

 All these theories are, however, tentative ; whether they will stand the test of 

 time, the future only can show. H. 



A MODEL FLORA. 



The Flora of Cheshire. By the late Lord de Table y (Hon. J. Byrne 

 Leicester Warren, M.A.) Edited by Spencer Moore. With a 

 Biographical Notice of the Author by Sir Mountstuart Grant Duff. 

 Pp. cxiv. + 399, with a Portrait of the Author, and a Map of the County. 

 London: Longmans, Green, and Co., 1899. Price 10s. 6d. 



Cheshire botanists will welcome the appearance of this flora of their county, 

 though an interval of close on quarter of a century has elapsed since the prepara- 

 tion of the materials now for the first time printed. During such a period 

 many changes must of necessity have taken place in details of local distribution, 

 but the flora has been brought as far as possible up to date by the editor, and 

 is a model of what a county flora ought to be. 



The author has devoted great attention to describing, often at considerable 

 length, the physical features, soils, etc., of the specific habitats, a point of great 

 biological importance, and one too often overlooked. Duly authenticated, and, 

 where possible, personal records are provided of the occurrence of each species 

 in each of the seven hundreds, and a striking feature of the book is the care 

 expended on the enumeration and history of alien and introduced species, many 

 of which are traced back to their origin in ballast heap or garden, while numbers 



