270 
TYPHOID FEVEE IX DISTEICT OF COLUMBL\. 
versa. On the other hand, Doctor Sprague showed that the colon 
bacillus occurs in the greatest numbers in the Potomac River water 
during the months of September and October, and attention is called 
to the parallelism existing between the death rate from tynhoid fever 
and the percentage of times the colon bacillus was found. 
Percentage of times colon bacilli were found in Potomac icater. 
Per cent of 
examina- 
tion 
present. 
1897. 
July 30 
August 33§ 
September 70 
October 70 
November 40 
December 20 
1898. 
January 20 
February 25 
Doctor Sprague states: 
That during the heated season the bacteria should be few is natural and easy of 
explanation. The anaerobic bacteria are at this time present in much greater numbers 
in proportion to the aerobic than at any other season of the year. Xow, in as much as 
the anaerobes indicate with a fair degi-ee of accuracy the amount of sewage contami- 
nation, it is e^'ident that from August to Xovember the Potomac River is more dan- 
gerously polluted than at any other season of the year. That there should be this 
relatively increased number of sewage organisms is equally as readily explained as 
that the total number of bacteria should be low. During the late summer and early 
autumn there is low rainfall, consequently few organisms are washed into the river 
from the surface of the earth, the source of by far the greater part of the bacteria present 
in water. 
During the season, however, the quantity of house sewage is appreciably above the 
yearly average, and it is from this source that the bacteria must come; hence we have 
a relative increase of the dangerous bacteria and a dimunition of the nonpathogenic 
varieties. At first glance it would appear that the highest typhoid death rate with the 
fewest organisms was contradictory, but when all the circumstances are taken into 
consideration it is at once seen that, so far from being a contradictory state of affairs, 
it is exactly what is to be expected. That the t^-phoid death rate, the presence of 
colon bacilli, the fermentation changes in the media and the temperature should coin- 
cide with one another is perfectly logical, and there is but one conclusion that can be 
drawn therefrom — the increased mortality from t^-phoid and diarrheal diseases is due 
to the increased quantity of bacteria from the intestines of man, which our citizens are 
compelled to digest at that time. The causal relation between impure drinking water 
and this death rate is so exddent to my mind that it is almost a criminal negligence to 
allow such an easily preventable condition of affairs to longer obtain in our midst, 
and it can be truthfully said that just so long as the inhabitants of this District are com- 
pelled to use Potomac water in its present state of pollution from 200 to 250 lives will 
be needlessly sacrificed annually. 
