60 
North Carolina Experiment Station 
MICROSCOPIC ANATOMY 
Microscopic anatomy as found in study of visceral organs of birds dying 
from avian typhoid under artificial infection conditions agreed, in general, 
with the microscopic anatomy as described in the typical field study as pre¬ 
sented under that heading. 
Heart. —The lesions of the heart and circulatory structures are consid¬ 
ered as of a secondary nature, and may be a condition of cloudy swelling, con¬ 
gestion, or even inflammation giving a parboiled appearance to the organ. 
FIG. 24.—GROSS WEIGHT OF KIDNEY IN NORMAL BIRD, AND IN TYPHOID BIRD 
OF SAME WEIGHT 
Liver.—The liver is dark, enlarged, and blood drips from the sectioned 
surface. Microscopic examination shows the cells in various stages of cloudy 
swelling and focal necrosis. Figure 26 shows a photomicrograph of a section 
of the liver, in which is seen at A, a congested vessel; B, a focal area of 
endothelial cell proliferation; C, a hepatic cell in a state of cloudy swelling 
or albuminoid degeneration. There may be observed small microscopic areas 
made up of a mass of small spheroidal cells, due to obstruction of liver capil¬ 
laries in part by proliferation of endothelium. Necrotic changes may develop 
in and around these focal cell accumulations. The focal necroses of the liver 
and of other parenchymatous organs is due to the action of toxic substances 
in the body fluids as a result of the infection. 
