1 98 Oranges and Lemons of India. 



species known at present. Some may have been pro- 

 duced by crossing, and by breaks, and others may be 

 descendants of some wild extinct species. There is no 

 reason why some of the original citrus, from which 

 our forms may be direct descendants, should continue 

 to exist any more than the Dodo, and other extinct 

 animals. It is hardly reasonable, therefore, when we 

 find some variety of citrus which is somewhat different 

 from others, such as the pummelo, for us to expect 

 that this must have some wild species in existence, from 

 which it has directly descended, and although we have 

 not discovered it yet, further search may probably 

 bring it forth. 



The birth-place of the genus citrus must have been 

 originally rather circumscribed, because it is not a 

 plant that can stand a very low temperature without 

 perishing. Of course now it is found all over the 

 world, wherever the temperature permits it to exist. 

 But all this dissemination has been largely done by 

 the hand of man, and within historic times. 



Indian forest officers say that the most destructive 

 agents to trees are forest fires, and these are often 

 produced intentionally by herdsmen, in order that the 

 old grass and scrub may be burnt, and by their ashes 

 the new grass nourished. If these forest fires can- 

 not be prevented now, just fancy what amount of 

 forest firing must have taken place in times when 

 man was still in a nomadic stage, and principally living 

 on the produce of his cattle, wandering from place to 

 place with his herds, firing here and there, never 

 caring how many timber trees he destroyed, and 

 how many species he extinguished, as long as he 

 got new grass for his cattle. Besides fires in the 

 nomadic stage, later on, during the agricultural stage, 

 invasions must have occurred, and the total disappear- 



