298 On Malaria. 



But to put this out of all doubt, while it serves to prove also 

 the power which we possess over this cause of mortality and 

 disease, it is sufficient to review the history of our own country, 

 or even of London, to be convinced that our climate is capable 

 of producing malaria wherever the other necessary circumstances 

 are present ; and that, in as far as we are now exempted, it 

 has been the consequence of an attention directed to these cir- 

 cumstances. Hence the reasons, and the inducements also, to 

 further attention of the same nature, for which it is primarily 

 necessary that we should possess an accurate knowledge of 

 them. 



How enormous and nearly incredible the diminution of agues 

 and fevers has been in Lincolnshire, Essex, Kent, or generally 

 in the fenny and marshy counties of England, since the agri- 

 cultural improvements of those lands, is matter of notoriety, 

 since much of it has even occurred in our own days : but even 

 in London, on Burnett's authority, the intermittent raged like a 

 plague in the reign of Mary ; while, from Sydenham, Morton, 

 and others, to whom we may add the testimony of Short, and 

 more recently, the facts collected by Heberden, the years 1658, 

 1664, and those from 1667 to 1692, were years of a mortality 

 from this cause, which, could that act now as it then did, would, 

 probably, in any one year, destroy twenty or thirty thousand 

 persons in London alone. And this national mortality from 

 fevers, from the fevers of malaria, extended even down to the 

 year 1729, according to Short's testimony — so recent are the 

 improvements by which it has been diminished. 



Here, then, it is at last proved, that the climate of England 

 did not then exempt it from malaria; and as that climate 

 remains the same, so must this poison be still produced ; what- 

 ever exemption we do possess, being the consequence of having 

 corrected or destroyed some of those places or soils by which it 

 is generated ; but we have not corrected them all, nor have we 

 exterminated the disorders which we have diminished. This is 

 the task which yet remains for us, and for that end it is, that I 

 shall here endeavour to point out the circumstances which do 

 produce malaria ; since I have, I trust, proved that it does 

 exist among us ; too generally overlooked, and not unfrequently 

 denied or even ridiculed, while the chief cause of this oversight 



