Is the Eucalyptus a Fever-destroying Tree ? 11 



population into any part of Australia, or diverge to any 

 point of the compass, we immediately observe the eucalyptus, 

 which is but seldom absent until we again enter some city 

 or town ; in fact, four-fifths of Australian vegetation consists 

 of the eucalyptus. 



In the consideration, therefore, of its climatic influence or 

 of its health-producing power over that of all other vegeta- 

 tion existing in other countries, we are able more efficiently 

 than elsewhere to deal with the subject. 



Physiologists explain the part taken by plants in general 

 to renovate the atmosphere and to supply to man and all 

 other living creatures a vitalising air, and sanitary reformers 

 have expatiated on the evils resulting from decayed vegeta- 

 tion under all circumstances ; but as regards the destruction 

 of malaria by the growth of certain trees, although this 

 means has been recommended from early times, the rationale 

 has been left an open question. 



Some trees and plants have the reputation of evolving 

 malaria, and in the countries where they grow the 

 inhabitants avoid camping under or about them ; in other 

 instances, the dewdrops of the morning from off some plants 

 have been known to irritate the skin in appearance like 

 fever spots, similar to what I have seen produced from our 

 ficus macrophylla. 



Such instances are traceable to some substance existing in 

 the plant, and have nothing to do with malaria. 



Whatever may be the theory adopted as to the causes of 

 zymotic fevers, whether it be " Liebig's Albuminoid," or 

 " Pasteur's Animalcular," they greatly abound in many 

 countries. 



Australia on the whole may be said to be pretty free from 

 virulent endemic or miasmatic fevers, and the latter may be 

 said to exist only as the eucalyptus recedes. 



The physical geography of Australia does not differ in its 

 general outline from that of other countries. We have 

 mountains and valleys, high ranges and extensive plains, 

 rivers and creeks, and according to Mr. Selwyn,* " in 

 general structure, character, and composition, in geological 

 sequence, and in physical and pal?eontological relations, the 

 rock formations in Victoria are in all respects analogous to 

 those of other regions." 



But in the eucalypti we have a vegetation absolutely 



* Intercolonial Exhibition Essay, 1866-7. 



