THE SWAMP FEVER OF HORSES. 
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hyperemic, and sometimes edematous. The bone marrow 
is much redder than is normal. 
In Mack's series of cases/* the petechise of the serous sur- 
faces were exceedingly numerous and they were occasion- 
ally confluent ; in addition there were distinct hemorrhages 
into many of the organs, as, for example, in the spleen and 
beneath the endocardium. In the same series of cases the 
meninges were much congested and hemorrhagic areas were 
described in the mucosa of the stomach. 
As is mentioned below, the epidemic of " Swamp Fever," 
described by the members of the Minnesota State Board of 
Health in 1903, was probably not identical with the disease 
which is known by that name in Canada. At the autopsies 
on cases of the disease described in Minnesota abscesses 
were frequently found ; pus has not been reported in the 
cases of Swamp Fever which have been examined in Canada. 
B. Minute appearances. — The heart muscle frequently 
shows cloudy swelling; sometimes the condition has gone on 
to fatty degeneration and actual necrosis. Hemorrhages 
may occur beneath the endocardium or epicardium and into 
the myocardium. 
The lungs may be congested and small areas of consolida- 
tion are occasionally seen. The alveolar cells often contain 
pigment. 
The liver is congested ; sometimes the hyperemia is 
intense, and blood may be extravasated into the substance 
of the organ as well as beneath its capsule. Areas of degen- 
eration, especially at the center of the lobule, are not uncom- 
mon, and sometimes the degenerated liver cells are more or 
less completely replaced by immigrating leucocytes, by 
plasma cells and by debris. The liver cells always contain a 
large amount of iron-bearing pigment. 
The spleen is congested and may contain areas of infarc- 
tion. It contains much iron-bearing pigment. Areas of 
amyloid degeneration, increase of fibrous tissue, and prolif- 
eration of endothelial cells in the lymph spaces have also 
been observed. 
