extent around the infected person within which such infection is
possible. Such spray formation is also an important means of the
extension of infection in the sick individual, for it is continually
formed and inspired. It is in this way that the extreme prevalence of
broncho-pneumonia in infants and young children is to be explained. No
matter what the essential disease, an almost constant finding in young
children after death is small areas of inflammation in the lungs in
and around the terminations of the air tubes. The situation renders it
evident that the organisms which caused the lesions entered the lung
by the air tubes. The mouth of the child is unclean and harbors
numbers of the same sort of organisms as those causing the lung
inflammation; but in the absence of such a mode of infection as is
given by spray formation it is difficult to see how the extension from
the mouth to the lungs could take place. The weakened condition of the
body in these cases favors the secondary infection.

If the disease be located in the intestines, as in typhoid fever and
dysentery, the organisms are contained in the fecal discharges, and by
means of these the infection is extended. In typhoid fever, dysentery
and cholera massive infections of the populace may take place from the
contamination of a water supply and the disease be extended over an
entire city. One of the most striking instances of this mode of
extension was in the epidemic of cholera in Hamburg in 1892. There
were two sources of water supply, one of which was infected, and the
cases were distributed in the city in the track of the infected
supply. Many such instances have been seen in typhoid fever. Certain
articles of food, particularly milk, serve as sources of infection.
This is more apt to happen when the organism causing the infection
grows easily outside of the body. A few such organisms entering into
the milk can multiply enormously in a few hours and increase the