Marshes and their Effects on Human Health. 57 
and hence it is not strange that the atmosphere became infected 
with poison too foul to breathe. 
But the enquiry comes up, if the atmosphere was infected with 
the seeds of dreadful diseases, why were its operations so gene- 
rally restricted to a given district? The reason is conclusive, 
scarcely a morning passed, from the middle of August until cold 
weather came on, but that a dense cloud of fog might be seen 
extending along the line of the rail way through the town. 
And very often as the morning fog passed off, it might be seen 
from the upper parts of the town, to follow up the streams that 
originate at the west mountain, and remaining longest over the 
precise territory where the disease principally prevailed, and with 
a density so great, that its upper surface, as seen from the eastern 
hills, did not appear to reach higher than half the altitude of the 
mountain. 
But these miasmatic vapors were in no wise limited to morning 
visitations, they often came on at early evening and made sure 
their sojourning through the night, and no doubt kept the whole 
atmosphere continually polluted with their poison, which the taste 
or smell of a person out and exposed to its influence could readily 
detect. The fever of 1840 continued, to a certain extent, to pre- 
vail until mid-winter and perhaps a few cases after that time; but 
a majority of them occurred between the first of September and 
the middle of December. 
Usual health prevailed in the place through the following 
spring and summer, which, like the corresponding seasons of the 
previous year, were marked with unusual drought. But in early 
autumn the sickness again commenced, extending over the same 
territory, and in many cases attended with similar fatal results. 
The rail road was completed and put in operation early in 1841, 
consequently the throwing up of these swampy lands was pretty 
much ended. But the poisonous effluvia of earth already dis- 
turbed was not removed, and the action of the elements upon it 
again produced similar results. In 1842 a few cases of the fever 
occurred, but the number, compared with that of the two previous 
years, was diminished at least seventy-five or eighty per cent; 
