How to reclaim the Nicohars. 93 



organisms, In conformity wdtli known chemical laws, are de- 

 stroyed under similar conditions, and, under the influence of 

 the atmosphere co-operating with humidity, ferment and 

 become decomposed. From all which processes result pro- 

 ducts of emanation, which, caught up into the atmosphere and 

 whirled away by the wind, become in their turn the means 

 of nutriment and fertilization to other plants, thus imparting 

 to tropical vegetation that marvellous rankness and super- 

 abundance so fatal to the human frame. But the conditions 

 wliicli produce this tendency in the atmosphere to generate 

 fever are not peculiar to certain localities, or strictly con- 

 fined to these; they can be averted, and with them the 

 vapours so prejudicial to health may be removed. We have 

 but to raise up a barrier against that mighty all-devouring 

 process of life and vegetation, which imperils our o^ai con- 

 ditions of existence, we have but to withdi'aw from the power- 

 ful agencies of chemical action the substances undergoing 

 decomposition, to constrain the waters of heaven to follow 

 certain definite directions, to drain every swamp, to clear the 

 forest, to sweep away the dense underwood in order that the 

 wind may wander unchecked over the now fertilized soil, 

 and a wondrous alteration will take place in the climatic con- 

 ditions of the Nicobar Islands. Of what mav be achieved 

 under such circumstances by energy and perseverance, the 

 island of Penang, some 350 nautical miles distant, fm-nishes 

 the most striking example, which within a very few decades 

 has, by dint of the progressive clearing and cultivation of the 



