NOTES ON ANOPHELES IN CEYLON. 275 



stricken people who eke out a miserable existence in a few scattered 

 villages. 



The opinion of the natives as to the causes of malarial fever is inter- 

 esting, founded as it has undoubtedly been from direct observations for 

 mauy years and probably the accumulated experience of centuries, and 

 it is interesting also to note that various medical officers serving 

 with the troops in Triucomalie have from their own observations 

 formed similar opinions to those held by the many intelligent natives of 

 the district. So long ago as 1798 Assistant Surgeon Colin Bogers, of 

 the 80th Regiment, gave in his medical report a very complete account 

 of the reasons which induced him to think that the cause of the malarial 

 outbursts were due to the South- West Monsoon blowing into the Fort 

 after traversing many miles of noxious jungle. He says : — 



" During a residence of 4 years at Trincomalie I have always observed 

 " that the season has been most healthy when the rains fall early in November 

 " or December and the setting in of the South-West Monsoon is late. In 

 " this case the North-East Monsoon or sea wind, continuing to blow for 

 " several months after the falling of the rain, the country is rendered in a 

 "' great degree dry and the unhealthy vapours are dispersed before the wind 

 " shifts to the south-west and blows over the land which in the neigh- 

 " bourhood of Trincomalie is in many parts marshy and almost entirely 

 " covered with jungle. The rains at Trincomalie commenced in November 

 " last and ceased early in January, since which time there has been dry 

 " weather with a regular sea breeze which continued to prevail until the 

 " end of April, by means of which the unwholesome vapours are blown from 

 " the Fort and the stagnant water will be nearly dried up before the mon- 

 " soon changes. 



" In the year 1797, on the contrary, during which the troops suffered much 

 " from remittent fever and berry-berry, the rains fell late in the season and 

 " the monsoon changed early in April, so that there was much moisture in 

 " the jungle and stagnant water on the ground when the south-west wind 

 " set in, and blowing over the land carried the unwholesome vapours towards 

 " the Fort and produced diseases similar in their nature and almost equal in 

 " their malignity to those lately contracted in the Candyan territory." 



It was in 1898, exactly one hundred years after the above was 

 written, that the medical officer in the same station attributed an 

 outburst of fever in Fort Frederick to precisely similar causes as his 

 predecessor had done a century previously. He writes : — 



" I attribute the great decrease in fevers to the f act;that the past year 

 " has been a very dry one ; very little rain fell after December 1897, so all 

 " the country was thoroughly dry before and during the hot weather (March, 

 "April, and May). The usual bad months proved healthy. There was a 

 " sudden large increase in fevers during June. It set in with the com- 



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