128 THE HOUSE FLY—DISEASE CARRIER 
veyecl by flies’ legs is not common in times of peace, 
“infection by the excrement of flies bred in infected 
material explains many conclusions formerly difficult 
to accept.” 
Chronic Carriers 
It becomes necessary at this stage to discuss the ques¬ 
tion of persons who become chronic carriers of typhoid 
germs, giving them out in their excreta and in their 
urine for perhaps many years. The application of this 
phenomenon to the fly question will be dealt with later. 
It was known in the United States prior to the Span¬ 
ish-American War that typhoid patients would give out 
bacilli in this way before the disease was diagnosed, 
and it was also known that some of them would give 
out the germs for perhaps several weeks after the fever 
abated and the patient was practically cured. And of 
course the walking typhoid or “ambulatory enteric” 
was known to exist; that is to say, slight cases which 
did not bring the patient to bed but during which germs 
must have been given off. True chronic carriers were 
not known in this country at that time, and the develop¬ 
ment of this extremely important phase of the typhoid 
question has been a recent one. The phenomenon was 
known in Germany before it was brought vividly to 
the attention of the American people. 
The first case here to receive general notice was that 
of “Typhoid Mary,” an Irish cook, who was discovered 
by Dr. George A. Soper, of New York. She had been 
cook with a family on Long Island, and during the 
summer of 1906 several cases of typhoid occurred. The 
