THE SWAMP FEVER OF HORSES. 
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Spleen (3^ pounds) : The capsule is somewhat thickened and the whole 
of its surface is dotted with very numerous petechial hemorrhages. 
Adrenals and pancreas : Normal. The bladder is normal and contains a 
fair amount of cloudy urine. The turbidity is caused by urates, although 
there are a few pus cells present. The marrow of the long bones is firm 
and yellow. The surface of the brain is somewhat congested ; the dura 
seems normal. The mucosa of the alimentary canal is normal throughout ; 
the gut contains a large number of Oxyuris equi and a few Sclerostomum 
tetracanthum. None of the lymph glands are markedly enlarged or con- 
gested ; one small abdominal gland is hemorrhagic and on section is 
found to contain a small filaria (Filaria papillosa). 
(b) Minute appearances. — Heart: Normal. Lung: Markedly con- 
gested. One section contains a very recent hemorrhagic infarct. Spleen : 
There is extreme congestion with small hemorrhages into the pulp. The 
secondary follicles are represented by a few cells. There is much bright, 
yellow brown pigment in phagocytic cells throughout the organ. The 
trabeculae contain many migrating polymorphonuclear leucocytes. Liver : 
There are a great many focal necroses of small size and irregular distribu- 
tion, each consisting of a few necrotic liver cells or of remains and 
collections of endothelial cells, lymphocytes, and occasional polymorpho- 
nuclear leucocytes. Many of the endothelial cells contain light brown 
refractive pigment. A few bile ducts contain inspissated bile but are not 
distended. Kidney: There is no pronounced lesion. The tissue is much 
altered by post-mortem changes. Pancreas : Post-mortem changes only. 
Adrenal : Normal. Muscle : Tissue from a skeletal muscle and from the 
diaphragm contains Sarcosporidium. Lymph glands: All show very 
marked congestion, but contain only small amounts of pigment. The 
sinuses contain only a few endothelial cells. In two glands the reticular 
tissue contains clusters of endothelial cells, some of which contain brown 
pigment; others are vacuolated. Brain cortex: Normal. Spinal cord: 
Normal. Peripheral nerve : Normal. 
Horse HL (Brown Mare). — Weight, 970 pounds; age, 10 On 
February 18, 1910, this horse was inoculated intraperitoneally with 20 
cubic centimeters of blood taken from Horse L (temperature 105.5^ F.). 
Eight days later there was a rise in its temperature for one day to 103° F. ; 
a similar rise occurred in the week following. Four weeks after the inoc- 
ulation the temperature rose on two successive days to 105.5° ^- The 
temperature then fell and, until the 20th of July, it remained between 100° 
and 101.5° F. The pulse rate was low ; during the first rise in temperature 
to 103° F. it was at 46; and during the rise to 105° F. it was at 53. No 
edemas or other gross clinical signs occurred and the animal put on flesh 
until it weighed over 1,000 pounds. On the 21st of July 970 cubic centi- 
meters of blood were transfused into its jugular vein from Horse V., which 
on the previous day had had a rise in temperature to 103.50 F. Sixteen 
days later there was a slight rise in temperature to 103.5° F. Since then 
to the present date, October 31, the temperature has been approximately 
