NA TURE 



26 



THURSDAY, DECEMBER 29, 1910. 



MALARIA PREVENTION. 

 The Prevention of Malaria. By Major Ronald Ross, 

 C.B., F.R.S. With contributions by Prof. L. O. 

 Howard and others. Pp. xx + 669. (London : John 

 Murray, 19 10.) Price 21s. net. 



FEW if any subjects bearing on the prosperity of 

 tropical lands can be of greater importance than 

 the effective control of those tropical diseases which 

 have often proved barriers, sometimes insuperable, to 

 their development. This will readily be admitted with 

 reference to the colonisation of such lands by white 

 men, but it is of at least equal importance for the 

 welfare of the indigenous races the progress of which 

 towards a higher civilisation is most intimately bound 

 up with an increased immunity from disease and a 

 higher standard of hygienic environment. 



Of all the diseases prevalent in tropical and sub- 

 tropical countries there is none to compare with 

 malaria, either, in point of view of frequency or of 

 disastrous results in respect of the general health of a 

 population. This has been acknowledged to a certain 

 extent from the earliest times, but it has been left 

 for modern science to demonstrate the true magnitude 

 of the problem and to point out scientific and prac- 

 tical measures by which the damage caused by malaria 

 may be controlled. 



In this volume, by Major Ronald Ross, we have an 

 admirable account of the whole of the many-sided 

 problem of malaria prevention, stated in clear and 

 eloquent fashion, and developing the subject in so 

 logical a sequence that the reader is carried in com- 

 plete sympathy with the author towards an accept- 

 ance of the preventive measures which he advocates 

 as being the best at present available. 



No one has better right to speak with authority on 

 every branch of the subject than the author, whose 

 discovery of the mosquito transmission of the disease 

 laid the foundation for the majority of the preventive 

 measures which have already been of inestimable ser- 

 vice to humanity. The discovery of the malarial para- 

 site by Laveran, epoch-making as it was, in itself did 

 little to help in the prevention of the disease, and only 

 a knowledge of the complete life-history of the para- 

 site could teach us where and how to apply measures 

 directed towards the prevention of this scourge of 

 humanity. 



Since this knowledge became available, numerous 

 books have appeared, in many tongues, dealing with 

 prevention, but the immense majority of these are 

 either purely technical or purely popular, and there 

 was a distinct place for a volume such as this, which, 

 while avoiding unnecessary technical and medical 

 detail, deals with each branch of the subject in com- 

 prehensive fashion and affords such a complete guide 

 as is imperatively needed by all who have to deal with 

 the subject practically, whether from the point of 

 view of the health officer or from that of the civil 

 administrator of a country or district. To obtain suc- 

 cess in a malaria campaign it is not enough to be told 

 what to do, one ought to know in addition the " why " 

 of each step. 



NO. 2148, VOL. 85] 



Throughout the whole of the work the author 

 speaks, as he obviously feels, strongly on the half- 

 hearted manner in which preventive measures have 

 been applied by many bodies in administrative control 

 of various malarious countries. He acknowledges 

 that in many instances the cause of this official in- 

 difference is apprehension of excessive expenditure, 

 but he shows clearly that, even from this low point 

 of view, a grudging expenditure is bad finance. 

 Granted that the measures he so ably advocates are 

 carried out with intelligence, and under continuous 

 and proper supervision, few who follow his arguments 

 and examples will differ from him that few items in 

 a colonial budget would have been better expended. 



After an interesting historical account of malaria, 

 from the earliest classical allusions to the discovery 

 of the parasites and of the mode of transmission by 

 anopheline mosquitoes, a clear account is given 

 of the fundamental observations and experiments 

 which have led up to our present-day knowledge. 

 Next follows a most interesting chapter on the para- 

 sitic invasion of man. This will be read with per- 

 haps the greatest interest by those who have prac- 

 tical knowledge of the disease, since it is replete with 

 information of the most valuable character on such 

 points as the number of parasites which may be 

 introduced by the mosquito, the number which must 

 develop from those introduced before illness is pro- 

 duced in man, the period of incubation, the limitation 

 of the invasion, &c. Even those who are familiar 

 with most of the subject-matter here dealt with will 

 find much to interest them, since there is scarcely a 

 point discussed which has not a direct bearing upon 

 the question of prevention. 



Major Ross lays great stress upon the necessity for 

 a more accurate study of the disease by exact quanti- 

 tative methods, and his arguments and illustrations 

 in connection with this point will find general accept- 

 ance. For instance, he advocates a more accurate 

 study of the numbers and local distribution of the 

 particular anopheline mosquitoes which are found to 

 transmit malaria in a given locality, since, without 

 such a foundation, it is not possible to judge with any 

 degree of accuracy as to the effects of the measures 

 which may have been adopted with a view to their 

 destruction. Again, in assessing the value of different 

 preventive measures, such as mosquito destruction, 

 the systematic use of quinine or the protection of 

 individuals by mosquito netting, an accurate measure 

 of the amount of malaria present in a particular popu- 

 lation is an essential preliminary. He devotes con- 

 siderable space to the best means by which such 

 estimations may be carried out, and discusses the 

 relative value of estimates of the actual number of 

 individuals who have parasites in their blood at a 

 given time, the estimation of the number who show 

 signs of present or recent infection by enlargement of 

 the spleen, the constantly-sick-rate, the death-rate, 

 &c. He concludes that the most generally useful of 

 these is the spleen-rate, since an actual microscopical 

 examination of the blood demands too great labour. 

 In this connection a good example of his mathematical 

 reasoning shows that in a quarter of an hour a careful 

 microscopical examination of a sample of blood for 



