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iphoid fever continue to discharge the bacilli in their stools or urine 
for years. One of these so-called bacillus carriers working in milk at 
a dairy farm or dairy may contaminate a can of milk from time to 
time and be the source of infection for a number of cases. It is easy 
to appreciate how much infection might be spread from a bacillus 
I carrier, such as the one so admirably discovered by Soper,® if working 
at a dairy farm or dairy. 
It is possible for persons in the early stage of the disease, and 
even before becoming ill enough to take to bed, to contaminate milk. 
The spread of infection from cases in the early stage has generally 
been considered of infrequent occurrence on the ground that the bacilli 
rarely appear in the urine before the end of the third week of illness 
and that few if any are discharged in the feces during the first week 
or two. On the contrary, H. Conradi, * * 6 who has made extensive studies 
on the conveyance of typhoid infection in Germany, states that he has 
reached the conviction that not only is the infection transmitted most 
often during the earliest stages of the disease, before its true nature 
has been recognized, but that it also frequently takes place during the 
incubation period. He bases this opinion on the observation that of 
89 cases which he attributed to infection by contact, some 58 per cent 
of the secondary cases had onset of illness in the first week of the ill- 
ness of the primary case, indicating that more or less of the secondary 
! cases must have received the infection during the incubation period of 
the primary cases. 
Flies passing from the infected excreta to the milk or the milk cans 
may readily convey the infection. 
The excreta of patients thrown into the privy or in the yard or field 
nearby may be carried by drainage, seepage, on the feet of persons, 
etc., to the well, spring, or stream from which water is used for wash- 
ing cans and so be conveyed to the milk. 
In country places there are frequent instances where chickens and 
other fowls have free access to the privy contents and may readily 
carry infection on their feet to the well. The excreta of patients, care- 
lessly handled, may become dried and carried as dust into exposed 
milk or more frequently into exposed milk vessels. 
Bottles or cans in some way contaminated at the house or dairy in 
the city and without previous disinfection are again filled with milk 
at the dairy farm may be the means of conveying infection from the 
dairy farm back to the city. 
At the dairy . — Milk after it reaches the city dairy is not only ex- 
posed to the danger of becoming contaminated by persons handling 
®“The Work of a Chronic Typhoid Germ Distributor.” Jour. Am. Med. Assn., 
Yol. XLVIII, No. 24, p. 2019. 
6 Deut. Med. Woch., Oct. 10, 1907. 
