156 
Sanitary Effect h of Land Draining. 
by experienced graziers ; and it is a matter of observation, that since the 
brooks and rivulets in the county of Lincoln have been better managed, 
and the system of laying ground dry, by open ditches and under-draining, 
has been more judiciously practised, the rot is become far less prevalent. 
Sir John Priugle informs us, that persons have maintained themselves 
in good health, during sickly seasons, by inhabiting the upper stories of 
their houses; and I have reason to believe that, merely by confining 
sheep on high grounds througli the night, they have escaped the rot." 
Dr. Harrison makes some observations on the effects of imper- 
fect drainage in aggravating the evils intended to be remedied, 
of which frequent instances are presented in the course of this 
inquiry, — 
" A grazier of my accpiaintance has, for many years, occupied a large 
portion of an unenclosed fen, in which was a shallow piece of water that 
covered about an acre and a half of land. To recover it for pasturage, 
he cut in it several open ditches to let off the water, and obtained an 
imperfect drainage. His sheep immediately afterwards became liable 
to the rot, and in most years he lost some of them. In 1192 the drains 
failed so entirely, from the wetness of the season, that he got another 
pond of living water, and sustained, in that season, no loss of his flock. 
For a few succeeding years, he was generally visited with the rot ; but 
having satisfied himself by experience, that whenever the pit was, from 
the weather, either completely dry or completely under water, his flock 
was free from the disorder, he attempted a more perfect drainage, and 
succeeded in making the land dry at all times. Since that period he 
has lost no sheep from the rot, though, till within the last two years, he 
continued to occupy the fen. . . . 
" Mr. Harrison, of Fisherton, near Lincoln, has by judicious manage- 
ment laid the greatest part of his farm completely dry, and is now little 
troubled with the rot, unless when he wishes to give it to some particular 
animals. His neighbours, who have been less provident, are still severe 
sufferers by it, nor are their misfortunes confined to sheep alone. Pigs, 
cows, asses, horses, poultry, hares, and rabbits, become rotten in this 
lordship, and have flukes in their livers. . . . 
" The late Mr. Bakewell was of opinion, that after May-day, he could 
communicate the rot at pleasure, by flooding, and afterwards stocking 
bis closes, while they were drenched and saturated with moisture. In 
summer, rivers and brooks are often suddenly swollen by thunder-storms, 
so as to pass over their banks, and cover the adjacent lowlands. In this 
state, no injury is sustained during the inundation ; but when the water 
returns to its former channel, copious exhalations are produced from the 
swamps and low lands, which are exceedingly dangerous to the human 
constitution, and to several other animals, as well as sheep. . . . 
" A medical gentleman of great experience at Boston, in Lincolnshire, 
and who is considerably advanced in life, has frequently observed to mc, 
that intermittents are so much diminished in his circuit, that an ounce 
of the cinchona goes further at this time in the treatment of agues than 
a pound of it did within his own recollection. During his father's prac- 
tice at Boston, they were still more obstinate and severe. For my own 
