December 29, 1923] 



NATURE 



931 



vears to a subject which demands no little concentration 

 of effort and an enthusiasm that is proof against the 

 dullness of tedious routine ; he has devised a method 

 )f scientific description which he believes to be an 

 advance upon all previous systems. The technical 

 value of this method can only be thoroughly tested by 

 specialists, but a mere botanist can at least appreciate 

 the soundness of the underlying principles and the 

 meticulous attention to details. The author is to be 

 congratulated on the successful completion of a labour 

 of love which is a contribution of great value to the 

 pharmacologist and to all botanists whose aim is to 

 acquire an orderly and thoroughly sound method of 

 describing plant structures. 



An adequate description of a plant must take account 

 not only of the characters in which it differs from allied 

 types, but also of those which it shares with other plants. 

 Pen-portraits aim at furnishing a summation of char- 

 acters, the replacement of sketches of habit by clear 

 descriptions based on a definite scheme which is given 

 in full and constitutes a very important feature of the 

 book. They do not rely upon detailed anatomical 

 drawings to supplement imperfect descriptions : a pen- 

 portrait, if thoroughly made, is self-sufficient and at 

 most needs only a well-labelled diagrammatic repre- 

 sentation of the plant organ under consideration ; it 

 brings into the description " as much as possible of 

 what is now generally considered as belonging to the 

 domain of drawings and plastic models, in other words, 

 it tends to make pictures more and more superfluous." 

 The diagrammatic illustrations are exceedingly clear, 

 and of a kind which might with advantage be adopted 

 as a model by authors of botanical text-books. 



The value of Prof. Moll's method was demonstrated 

 by the junior author, Dr. Janssonius, in his book, 

 published in 1906, on the micrography of Javan trees : 

 an extension of the same method to timber trees of 

 other regions would be a great boon to botanists, especi- 

 ally to such as are interested in the identification of 

 fossil angiospermous woods. 



The prefaix', which is much more than a preface in 

 the ordinary scihc L;i\t s a clear account of the history 

 of descripti\'( bniaiiv, with special reference to micro- 

 scopical features, and emphasises the importance of a 

 more definite employment of the Linnean method in 

 micrography. Prof. Moll considers that the principal 

 feature of the Linnean method is its conformity to a 

 sequence fixed beforehand ; if it is rigorously followed, 

 completeness is achieved and nothing is omitted by 

 chance. A high standard is set, and the '* guiding 

 schemes," if the student has sufTicicnt faith and 

 patience to adopt them, supply the means of con- 

 structing pen-portraits according to the admirable 

 patterns contained in this great work. Most of the 



NO. 2826, VOL. I 12 I 



volume is devoted to descriptions of drugs arranged 

 in alphabetical order — Amylum, Cortex, Flores, Folia, 

 Fructus, etc. — and a full bibliography is added. 

 In illustration of the method, the headings of the 

 section deaUng with Cortex Cinnamomi may be 

 given : inacroscopic characters ; anatomical characters, 

 followed by a list of references ; epidermis, including 

 measurements of cells ; cortex, cork, phellogen, phello- 

 derm ; primary cortex ; endodermis ; stele, including 

 detailed description and cell-contents of the tissues ; 

 micrography of the powder, bast fibres and other cells, 

 crystals, starch grains, etc. A word of praise is due 

 to the publishers for the printing and style of the book, 

 and to the authors for their decision to present their 

 work in well-written English. A. C. Seward. 



Our Bookshelf. 



Text-hook oj Agricultural Bacteriology. By Dr. F. Lohnis 

 and Prof. E. B. Fred. (Agricultural and Biological 

 Publications.) Pp. ix + 283 -I- 10 plates. (New York 

 and London : McGraw-Hill Book Co, Inc., 1923.) 

 15s. 



Dr. Lohnis' " Vorlesung liber landwirtschaftlicher 

 Bakteriologie " has for so long been regarded as an 

 essential text - book, that students of agricultural 

 bacteriology will especially welcome the excellent Eng- 

 lish edition of this work which the author has produced 

 in collaboration with Prof. E. B. Fred. 



The authors devote the first portion of their work to 

 a description of the characteristics and general activities 

 of micro-organisms. This part of the book contains 

 useful chapters in which the general methods used in 

 studying the organisms are discussed. The second half 

 of the book is devoted to the special fields of bacterio- 

 logy that touch upon the problems of agricultural 

 research and practice. There are chapters on the 

 bacteriology of silage, hay, and other food materials, 

 on milk, butter, and cheese, on the methods of sewage 

 disposal, on the changes involved in the making of 

 farmyard manure and on the problems of soil biology. 

 In these chapters the authors deal with their subjects 

 with remarkable clearness. The very different prob- 

 lems that arise in these fields of work make it very 

 difTicult to connect them as though they formed a single 

 branch of applied science. It seems that the sequence 

 of thought would have been better preserved in this 

 portion of the book if the bacteriology of soil had been 

 considered before that of dairy products, because, in 

 the former subject, the problems involved so com- 

 pletely cover the field of microbiology, that the authors 

 have already been obliged to refer to the chief groups 

 of soil bacteria to illustrate the acti\itics of bacteria 

 in general. In dealing with the bacteriology of soil 

 and of dairy products, the authors discuss some of the 

 special methods used in these fields of work. In a 

 later edition, the description of special methods might 

 well be given in greater detail. At present, lack of 

 standardisation in technique greatly hinders work with 

 bacteria, and this is especially the case with soil and 

 dairy bacteriology. A detailed description of the best 



