August, 1909.] 



145 



Miscellaneous Pesls. 



The alternative mode of distribution 

 mentioned by Engler and Prantl, where- 

 by the seed, shaken out from the fruit 

 as it falls, sticks to any opposed object, 

 is, I believe, of such rare occurrence as 

 to be negligible, although the seeds are 

 frequently dropped by birds, feeding on 

 a branch, on the ground beneath. 



PROFESSOR ROSS' LECTURE 

 BEFORE THE ROYAL INSTITUTION 

 OF GREAT BRITAIN. 



(From the African Mail, Vol. II., No. 85, 

 May, 1909.) 

 On 7th May, Sir Francis Laking, Bart., 

 G. C V. O., Vice-President in the chair, 

 Major Ronald Ross (Nobel Laureate) 

 read a paper before the Royal Insti- 

 tution of Great Britain on "The Cam- 

 paign against Malaria." The following 

 are extracts from the above paper : — 



More than nine years ago I had the 

 privilege of addressing the Royal Insti- 

 tution on the subject of my researches 

 on the mode of infection in malarial 

 fever ; and I am now called upon to des- 

 cribe what has been done, or not done, 

 in various countries to utilise for the 

 alleviation of the disease the information 

 then obtained. 



As described in my previous lecture, 

 the broad principles of this theorem 

 were really fully established by the end 

 of the year 1898. Although numerous 

 minor details still required study — such 

 as the precise species of mosquitoes 

 which carry the infection in various coun- 

 tries, the exact habits of each species, 

 and so on, — yet I held that these ques- 

 tions could now be elucidated without 

 dfficulty in the ordinary course of work, 

 and that we are already in a position to 

 apply the discovery at once to the sav- 

 ing of human health and life. I propose, 

 therefore, to take up the story again 

 from this point. 



First, let me emphasise the great im- 

 portance of this practical side of the 

 subject. Malarial fever is spread over 

 nearly whole of the Tropics, abounds 

 in many temperate climates, and lias 

 been known to extend as far north as 

 Sweden. In vast tracts of Tropical 

 Africa, Asia, America and of Southern 

 Europe, almost every town and village is 

 infested by it ; millions of children suffer 

 from it from birth to puberty ; and native 

 adults, though they tend to become parti- 

 ally immune, still remain subject to 

 attacks of it. Although it is not often 

 directly fatal, yet it is so extremely pre- 

 valent, so edemic in locality, so persistent 

 in the individual, that the total bulk of 

 19 



misery caused by it is quite incalculable. 

 More than this, its special predilection lor 

 the most fertile areas renders it economi- 

 cally a most disastrous enemy to man- 

 kind. Throughout tropical life it 

 thwarts the traveller, the missionary, 

 the planter, the soldier, and the adminis- 

 trator. From one-quarter to one-half of 

 the total admissions into military hospi- 

 tals are returned as being due to it, and 

 it is often the most formidable foe which 

 military expeditions have to encounter. 

 There are reasons for thinking that it 

 directly increases the general death-rate 

 of malarious countries by something like 

 50 per cent., and I venture to say that 

 it has profoundly modified the history of 

 mankind by doing more than anything 

 else to hamper the work of civilisation 

 in the Tropics. Only those who have 

 studied the disease from house to house, 

 from village to village, can form any 

 true notion of the total effect which it 

 must produce throughout the world. 



Next let us recall briefly the various 

 methods which we possess for preventing 

 and reducing the disease. The oldest 

 of these — known to us siuce the time of 

 the Romans— is drainage of the soil. The 

 reason why it succeeds became quite 

 obvious after 1898— because it tends to 

 remove the terrestrial pools and marshes 

 in which the Anophelines, that is, the 

 family of mosquitoes which carry mala- 

 ria, breed. But the new discoveries not 

 only explained the old method, but also 

 rendered it more simple, cheap, and yet 

 precise by showing us exactly what 

 waters, namely, those in which the larvae 

 of the Anophelines actually occur, are 

 to be drained away, or filled up, or 

 otherwise treated. But science has given 

 us other methods as well. Thus we have 

 known for a long time that quinine is a 

 preventive as well as a cure— that if, for 

 example, a body of men are given qui- 

 nine with regularity they will suffer less 

 from fever in cousequence. Still further, 

 the old sayiug that the use of mosquito 

 nets at night will keep off malaria was 

 now fully justified— uot because the nets 

 exclude any serial poison, but simply be- 

 cause they exclude the infecting insects. 



This simple precaution can, moreover, 

 be extended by protecting all the win- 

 dows ot a house by ivire gauze, as already 

 frequently done in the Southern States 

 of America. Punkas and electric Jans 

 aiso serve to keep away the insects ; and 

 lastly, segregation of Europeans from 

 native quarters, as used so largely in 

 India, will help to keep them from 

 mosquitoes infected by native children 

 (who suffer so frequently from the 

 disease). It was thus apparent that if the 

 inhabitants of malarious countries could 

 be persuaded to protect themselves by 



