May 28, 1891] 



NATURE 



75 



and secondly, whether, if such organized poisons should 

 gain access, there is any sufficient guarantee or not that 

 they will be destroyed or removed before the water 

 reaches the consumer. It is because the chemical analysis 

 aflfords us at present a better clue than the bacteriological 

 examination as to whether a water has received sewage or 

 not that it is of more general applicability than the 

 latter ; but we must appeal to a bacteriological inquiry 

 in order to ascertain whether, in the event of sewage 

 gaining access to the water, there is a guarantee in the 

 subsequent history of the water that the zymotic poisons, 

 which may at any time accompany the sewage, would 

 undergo removal. In short, the object of nearly all 

 water examinations is obviously to ascertain whether the 

 water may at any time be dangerous to health, and not, 

 even if this could be with certainty determined, whether 

 it contains a zymotic poison at the particular moment of 

 examination. On the other hand, the fact that the 

 microbe, which is now pretty generally accepted as the 

 inducing cause of typhoid fever, has been on more than 

 one occasion actually discovered in drinking-water which 

 was under suspicion of producing an epidemic of that 

 disease, affords most important evidence as to the manner 

 of its distribution. 



There is much need of a similar work to this in Eng- 

 lish, as each year an increasing number of younger 

 medical men are coming forward for the degrees in Public 

 Health which are now granted by several of our Uni- 

 versities, and to these a practical and critical treatise 

 such as this would prove of great value. It is of great 

 importance that such Public Health students should be 

 impressed with a sense of the responsibility which 

 attaches to the examination of waters for domestic pur- 

 poses, and that most serious mischief may and often does 

 result from such investigations being intrusted to incom- 

 petent persons. It is gratifying to see that the authors 

 do not undertake to prescribe any of those artificial 

 standards of purity for drinking-water which so frequently 

 figure in books of this kind, and which are attended with 

 the greatest danger, leading as they do the ignorant to 

 believe that they can pronounce upon the fitness or other- 

 wise of water for drinking purposes from the numbers 

 which they have obtained in a few simple quantitative 

 ■determinations. For it must never be forgotten that the 

 sanitary examination of water is surrounded with such 

 difficulties that it is only by bringing to bear on each par- 

 ticular case all the evidence that it is possible to obtain, 

 and then interpreting this evidence by the light of an 

 extended experience, that a sound judgment can be 

 arrived at. P. F. F. 



OUR BOOK SHELF. 



Botany : a Concise Manual for Students of Medicine and 

 Science. By Alex. Johnstone, F.G.S. (Edinburgh and 

 London: Young J. Pentland, 1891.) 

 During recent years many books on botany have been 

 published, specially for the use of students preparing for 

 examinations. In these a few types and phases of plant 

 life have been described somewhat in detail. In the 

 present case a much wider range has been taken, the 

 result being an illustrated botanical note-book, condensed 

 but not meagre. In the preface the author takes it for 

 granted that every student nowadays attends lectures 



NO. 1 1 26, VOL. 44] 



or demonstrations, and " therefore does not so much 

 require a manual with diffuse explanations, but rather a 

 kind of illustrated digest and general note-book, which 

 will enable him to quickly arrange and make most effec- 

 tive use of the various facts and theories treated of by his 

 teacher." A book on these lines Mr. Johnstone has been 

 successful in producing. It consists of 260 pages and 226 

 illustrations. Some of the latter are the ones which seem by 

 custom to be considered necessary for reproduction in every 

 fresh botanical manual, while others appear to be new. 

 The outline ones, such as those on p. 30, illustrating the 

 branching of cells, give a much clearer idea than could 

 be done by pages of letterpress. A short introductory 

 chapter points out the position botany holds in science. 

 The strictly botanical part of the work is treated of in 

 four sections, viz. (i) morphology ; (2) external morphology 

 or organography ; (3) physiology ; and (4) taxonomy. 



Under morphology, the structure, life-history, contents, 

 and modifications of the cell as an individual are first 

 treated of, after which the combinations of cells to form 

 tissues are described, a special chapter being reserved for 

 the consideration of systems of permanent tissues. The 

 section on external morphology will be found very useful 

 to beginners in systematic botany. It could be wished 

 that the chapter on physiology, although containing much 

 useful information in its 15 pages, had been more 

 extended. The greater part of the remainder of the 

 book is devoted to taxonomy, in which the leading 

 characters of each class (arranged in ascending order) 

 are given, followed by the names of some of the genera, 

 which may be regarded as typical of their respective 

 classes, and interspersed with illustrations. The orders 

 of Angiosperms most frequently met with are represented 

 by short diagnoses and floral diagrams. A useful glos- 

 sary and index complete the book. 



The arrangement throughout the book is good. The 

 various headings, &c., printed in type differing according 

 to their importance, have been very carefully set out, and 

 give a good restun^ of botany in a tabular form. As an 

 illustrated note-book for a teacher, as well as a student, 

 this work will be "found of great use. C. H. W. 



Hand-book of the Ferns of Kaffraria. By T. R. Sim, 

 Curator of the Botanic Garden, King Williamstown, 

 South Africa. 66 pages, 63 plates. (Aberdeen : 

 Taylor and Henderson, 1891.) 

 This little book contains popular descriptions and outline 

 plates of the ferns of Kaffraria, with a chapter of defini- 

 tions of the botanical terms used in describing ferns, and 

 another giving directions how to cultivate them. The 

 Cape, considering the general interest and remarkable 

 individuality of its phanerogamic flora is very poor in 

 ferns. Kaffraria yields only 68 species, about the same 

 number as Great Britain. Amongst them are two tree 

 ferns, a Cyathea and a Hemitelia, and several herbaceous 

 species of a distinctly subtropical type, such as Vittaria 

 lineata and Marattia fraxinea. Associated with these are 

 several species with which we are familiar at home, such 

 as Aspidiuni aculeatum, Cystopteris fragilis^ and Adian- 

 tum Capillus- Veneris. No doubt by further exploration 

 the list will be considerably increased. The author does 

 not seem to have known anything about the Rev. R. 

 Baur, a Moravian missionary who made large collections 

 of ferns and other plants in Transkeian Kaffraria. The 

 two new species which Mr. Sim claims to have added to 

 the Cape flora cannot be admitted as novelties. Blechnum 

 remotutn is a variety of the American B. hastatuni, which 

 I do not think can stand as distinct specifically from 

 the common Cape B. australe. The plant figured as 

 Lomaria lanceolata on Plate 25 is no doubt Lomaria 

 inflexa of Kunze, which was gathered long ago in the 

 colony, by Gueinzius, and is beautifully figured by Kunze 

 from specimens which he forwarded. By the aid of this 

 book there can be no difficulty, even to an amateur, in 



