74 



NATURE 



[May 25, 1905 



Again, granted that Anophelines have been dimin- 

 ished in numbers in a certain area, it by no means 

 follows that the malaria will be diminished. We could 

 furnish many instances observed by us in Africa where 

 Anophelines were extremely scanty (but present) yet 

 the malarial index was high. In fact, it is not 

 always possible to trace any relation between the 

 number of Anophelines and the value of the malarial 

 index, although on the contrary it often is so. 

 Finally, we may point out that we have at our dis- 

 posal an accurate and easily applied method of 

 determining whether anti-mosquito measures have 

 diminished malaria. It is now universally accepted 

 bv medical men, but not generally known to the lay- 

 man, that the great source of malaria in the tropics 

 lies in the native children, who to the outward eye 

 show no signs of ill-health, though they contain in 

 their blood malarial parasites. The malarial index 

 or endemicity is the percentage of children under ten 

 j'ears of age that harbour parasites. It is not 

 uncommonly 100 per cent. 



If, then, the anti-malarial measures have reduced 

 malaria, this figure must decrease. If malaria has 

 been abolished it must be zero. (It is hardly 

 necessary to state that, in determining this index, 

 children of the same age must be selected for com- 

 parison, and the comparison must be made at the 

 ■same time of the year before and after operations ; 

 such precautions are obvious, and are, of course, 

 always taken by those engaged in such observations.) 

 To sum up, no facts are convincing where this proof 

 is not adduced. If the malarial endemicity is reduced 

 to zero, then anti-mosquito measures have been 

 •completely successful — but not until then. 



Let us return, however, to the book. We think it 

 would have been advantageous, considering the great 

 importance of the subject, if the authors had compiled 

 a tabular statement of those species that are known 

 to transmit malaria in nature, though the data on this 

 point can be found by search. At present, then, out 

 of twenty-four Indian Anophelins it has only been 

 shown that three convey malaria in nature, viz. : — 

 M. culicifacies, by Stephens, Christophers, and James ; 

 M. lisioni, by Stephens, Christophers, and James ; 

 P. fidiginosus, by Adie ; and we know with practical 

 certainty that M. rossii does not. The third chapter 

 contains many interesting details of larval life, but it 

 is to be hoped that many observers, using this book 

 as their guide, will study the subject further and fill 

 up the many lacunae. 



Chapter iv. is devoted again to the vexed question 

 of classification. Then follows part ii., containing 

 the systematic description of each species. The de- 

 scriptions are excellently done, clear, and sufficient, 

 and not overloaded with details which terrify the 

 already overburdened medical man in the tropics. In 

 fact, this book admirably fulfils the object of enabling 

 " medical men engaged in tracing the connection 

 between mosquitoes and human disease to identify 

 and speak with precision of the species implicated." 

 These words are attributed to Prof. Ray Lankester, 

 and if they represent his words we cannot but think 

 that the elaborate monograph of the Culicida, excel- 

 NO. 1856, VOL. 72] 



lent as it is, issued by the museum authorities has 

 not had this result. The majority of medical men 

 in the tropics can ill afford the time or inclination to 

 read these detailed descriptions. We think if the 

 museum authorities would issue concise but adequate 

 accounts of, say, the Anophelinse only, medical men 

 would be greatly helped. For a few shillings the 

 United States authorities publish excellent bulletins 

 on various subjects, e.g. the ticks, the flukes, and so 

 forth, but if a medical man in British possessions 

 wants to identify the species of tsetse-fly he is 

 working with he must buy a monograph issued by 

 the museum costing fifteen shillings. If he wants to 

 know anything about ticks, the museum leaves him 

 in the dark. Seeing what medical men have done 

 recently in elucidating malaria, sleeping sickness, 

 and, most recently of all, tick fever, we think they 

 might reasonably expect some help in return. W'e 

 would point out finally one small matter which might 

 be corrected in a future edition. In the list of illustra- 

 tions only i-x are mentioned, though these number xv 

 at least. The arrangement of the plates is erratic, 

 e.g. v, xi, vi, xiv, vii, &c., so that they are very 

 difficult to find. The proofs have evidently been care- 

 fully read, and we have detected no error of any 

 importance. 



The authors have had the great advantage of 

 describing species caught on the spot and studied 

 under their natural surroundings. We trust some- 

 body will be found in .•\frica to write an equally good 

 text-book of African Anophelines. 



We think that all medical men in India will feel 

 grateful to the authors for this excellent work. 



J. W. W. Stephens. 



EXERCISES IN PHYSICS. 

 Notes and Questions in Physics. By Prof. John S. 



Shearer. Pp. vii -|- 284 ; illustrated. (New York : 



The Macmillan Company; London: Macmillan and 



Co., Ltd., 1904.) Price ys. 6d. net. 

 nnHE present volume has been written to take the 

 -L place of a similar book prepared several years 

 ago by Prof. C. P. Matthews and the author. Actual 

 experience in the class-room indicated the desirability 

 of certain extensions and changes in the text, and also 

 of many explanatory notes and solutions. 



The book is, in reality, a collection of problems — 

 many of which have been selected from examination 

 papers— together with occasional hints with regard to 

 solving them, and very brief introductory paragraphs 

 to each section which explain the principal technical 

 terms referred to therein. It will be easily under- 

 stood, therefore, that the book is not intended to take 

 the place of regular text-books, lectures, or of labora- 

 tory practice. It is designed, indeed, to accompany 

 these. The supply of problems in many text-books is 

 exceedingly scanty — the present volume amplifies the 

 supply. It will be found of great service to the teacher 

 in suggesting problems to set as class work. As no 

 answers are given, there will be less temptation to the 

 teacher merely to quote the selected problems; anyone 

 who is alive in his subject will modify them to suit his 



