ECONOMIC EFFECT OF SANITARY WORKS. 125 
vile and noxious gases: in those days the population, which 
amounted to about 80,000, had to be supplemented by large 
importations from the country owing to the dreadful mor- 
tality caused by filth diseases: in 1307 the river Thames 
became so fouled and choked with all manner of filth, that, 
incredikle as it may appear, it actually became inaccessible 
to ships: foecal matter, urine, garbage, and other filthy 
ordure was cast indiscriminately into the street and foot 
passengers generally preferred the centre of the road for 
fear of having the contents of domestic utensils emptied on 
their heads from upper story windows; cesspools, which 
were the luxury of the rich, were emptied by pumping into 
the street gutters, the effluent finding its way to the lowest 
levels, thus breeding disease and death: is it any wonder 
that horrible epidemics like the spotted plague, the black 
death, sweating sickness, dancing, mewing and biting 
mania, and other horrors of filth production raged amongst 
the population. Prof. Corfield states that black death 
killed one-third of the inhabitants of the old world in one 
invasion. 
In 1531, Henry VIII., appointed the first commission to 
report on sewers, it was renewed in 1548 by Hdward VI., 
and it was extended by James I., in 1607, and subsequently 
other districts were granted similar commissions as the 
population increased and extended; there are no records 
of the accomplishments of the earlier commissions, but in 
1637 the important work of bridging and covering in of the 
Fleet ditch was completed, and it is probable, from the 
evidence of the death rate between the years 1531 and 1637, 
that very little else was done up to that date to remedy 
the insanitary state of the city; the covering in of the 
Fleet ditch appears to have produced slightly beneficial 
results, for between the years 1600 and 1650 the death 
rate decreased from 233°5 per thousand to 216°8 per thou- 
