40 



at most only iti the outskirts, nnd citj' night ail' is really better than that 

 of the day time, because there is less dust in it. 



The widespread use of quinine today is also traceable to the days of 

 much malaria. Then it was given in almost every case of sickness, a sort 

 of panacea, and this practice is simply kept up, not only by the people but 

 by many doctors. Today quinine really has a verj- limited use. The so- 

 called "False malaria" of our cities has no nOationship to malaria proper; 

 it is simply a reaction due to bad air. and not to the Plasmodium malaria. 



In the early days, when there Wiis i)ut little quinine, and that high 

 priced, many of the native barks and herbs were used. iiotal>lj- the Dog- 

 wood, Yellow I'opiar, AS ild Cherry, Thoroughwort and American Centaury. 

 They were steeped In v.hisky and formed "bitters;" l)itters still survive 

 and sonie are widt ly advertised in the newspapers; as a rule their value is 

 nil. A numi)er of other things concerning malaria might be mentioned, 

 but I must desist and will close this account with a few remarks on Adap- 

 tation and Immunity. 



We know that plants and animals are adapted to their surroundings 

 and that few can bear any marked change of environment ; wet soil and 

 dry srjil plants can not exchange places, nor can tropical animals exchange 

 places with those of the frigid zones. But many of our cultivated plants 

 and animals have been shifted about so much that they are able to tlour- 

 ish under a variety of surroundings, just as the white man flourishes be- 

 cause he has had such a varied experience in the past. Now there is also 

 an adaptation in the case of diseases. Where a disease has long been in 

 .1 country or locality, there is a mutual adaptation between the disease and 

 the people, or in other words, between the parasite and the host. If a dis- 

 ease is so virulent that it kills off all the people, then the disease in turn 

 is killed oft. or dies out, for want of material. If on the other hand, a dis- 

 ease is not strong enough to attack at least some members of a community, 

 then it is apt to i)e mild and to pi'k out and live only on the weak and 

 feeble or aged or the very young, the robust adults escaping. But where a 

 disease gets among a people who have never had it then it may be very 

 destructive, uianj may perish and few survive, but the survivors may re- 

 people the territory with a stock less susceptible, and we can see how. in 

 the course of ages, with a killing off or weeding out of the susceptible, a 

 strain may be jjroduced that is able to live in the presence of the disease. 



Examined in this light ^e get some clew to the original home of ma- 

 laria, rhe negro of Africa, is quite immune against malaria ; there is an 



