THE SWAMP FEVER OF HORSES. 
219 
The hemoglobin is much reduced; an estimate of the amount 
present may only give thirty to fifty per cent. 
As the disease nears its end the weakness and emaciation 
become extreme. The heart labors so that its beating is 
easily seen and sometimes it can be heard at some distance. 
Sweating, whether in small areas or over the whole of the 
body, often occurs ; death follows from exhaustion or from 
syncope. 
Though the disease may progress steadily towards a fatal 
termination there are, as a rule, temporary improvements 
during which the animal seems to be about to recover. 
Almost invariably, however, there is a relapse. A few 
extremely acute cases may die in two or three weeks ; the 
disease ordinarily lasts for two or more months; chronic 
cases may live for many months or even for years. Most 
veterinarians believe that the disease is always fatal. The 
animal insurance companies state that seventy per cent of 
the death claims made in Manitoba for horses are made 
because of Swamp Fever. 
A fatal disease, locally called Swamp Fever, occurs among 
horses in Minnesota. In 1903 the State Board of Health 
published a very complete report on it.^ In addition to 
giving an excellent description and recording the investiga- 
tions made by the Board the report contains a bibliography 
of Swamp Fever. 
The disease described in Minnesota presents, in a much 
more severe form, all the symptoms as it is observed in 
Canada. The Minnesota disease is usually an acute one and 
the animal may die within a week, or two and before the 
anemia has become excessively pronounced; the usual dura- 
tion is from four to six weeks. On the other hand, the 
anemia may be extreme in cases in which the disease lasts 
longer; for example, there may be only twenty per cent of 
hemoglobin and less than a million red cells. 
An ulcer is sometimes seen within the lower lip of horses 
with this affection and the petechiae of the mucous mem- 
branes are much more marked than they are in the Canadian 
disease. There may be distinct hemorrhages beneath any 
