170 CEYLON BRANCH— ROYAL ASIATIC SOCIETY. 



ring the great dry weather that is between May and October 

 the first month is healthy, the next three much less so, and the 

 last two again very salubrious. From this I would deduce that 

 a great portion of the sickness during June, July and August 

 is caused by the drying up of tanks in the neighbourhood, and 

 also perhaps by malaria transported by the north-east monsoon 

 from the long track of low swamp jungle which extends towards 

 Anoorajapoora. In September and October the tanks are on 

 the other hand quite dry, the shell-fish and plants are no longer 

 putrifying in the sun, and the station is heaithy. This does not 

 occur however, till after about four months of nearly perfect 

 drought. In November, December and January there is al- 

 most constant rain, exposure to which produces catarrh, feverj 

 &c. and by a reference to the diagram on which the average 

 appearances of fever are detailed, it will be observed that this 

 disease is more prevalent during and immediately after the great 

 rains than at any other period. 



During February and March there is little rain, there not be- 

 ing time however, for the tanks to dry up entirely, the state oi 

 health is almost identical with that of June, July and Au- 

 gust when as shown, the circumstances are in this respect 

 precisely similar. 



To put this hypothesis to the test I have carefully exa- 

 mined some of the diagrams for individual years, especially 

 those which deviate most in regard to time from the average curve, 

 for it will be observed that in every year there is a precisely 

 similar double rise and fall, but occasionally the time when these 

 oscillations occur is premature or is unusually delayed. If it 

 can be shown then, that when a season generally healthy, in one 

 year is found not to be so, and that such an appearance is in- 

 variably accompanied by a corresponding alteration in the oc- 

 currence of the dry and rainy seasons, then it will I think be 

 satisfactorily shown that, the insalubrity of Putlam (such as it is,) 

 is owing mainly to two causes. 



