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North Carolina Experiment Station 
tion of drinking water, confinement of birds to new range grounds if pos¬ 
sible, and the vaccination of all well stock. Splendid cooperation was af¬ 
forded the department by the County Agents and Agricultural High School 
teachers in outbreaks which could not be reached from the Poultry Patho¬ 
logical laboratories. 
The first comprehensive work in vaccination was that of Jenner in 1796. 
Jenner succeeded in producing immunity against smallpox by using cowpox 
virus, but was unable to scientifically establish the body processes by which 
immunity was accomplished. Pasteur in 1879, in his studies with the or¬ 
ganism of Fowl Cholera, brought out the important possibility that the 
virulence of a virus or germ might be so attenuated that its administration 
is not followed by the actual disease, but by the stimulation of body cells to 
the production of scientific antibodies. Since the work of Pasteur, serology 
and vaccine therapy has been the subject of exhaustive investigation and 
research. ! 
FIG. 28.—PHOTOMICROGRAPH OF A SECTION OF A TYPHOID LUNG. 
A. congestion of blood vessel, b. serous effusion 
Kolmer (19) defines a vaccine as a “sterilized and enumerated suspension 
of bacteria which furnish, when they dissolve in the body, substances which 
stimulate the tissues to a production of specific bacteriotrophic substances, 
which fasten upon and directly or indirectly contribute to the corresponding 
bacteria (Wright).” 
The use of vaccines in poultry husbandry is limited to a certain degree. 
Such work, to be useful, must necessarily be placed on an ultra-practical 
basis. Owing to the small value of the individual bird, and the relative short 
span of life, the general use of vaccines is not favored by the flock owner. 
The vaccine must be readily available, and of a low cost to secure usage in 
disease outbreaks. 
