CARRIAGE OF DISEASE 
113 
The true cause of the disease was not known until 
1880, when it was discovered by Eberth, and it was 
not long before it was isolated and studied in pure cul¬ 
ture. Technically this organism is known as Bacillus 
typhosus. It is isolated from persons who are sick with 
typhoid fever or who have been sick from it, and only 
from such persons. The disease which it causes is an 
intestinal disease, and through the multiplication of 
the bacilli in the body, and with a poisonous substance 
which it produces, conditions are caused which give 
rise to the characteristic symptoms of the disease. 
Ulcerations of the intestines and enlargements of the 
spleen and mesenteric glands follow, and the bacilli 
frequently invade other portions of the body, such as 
the kidney, the liver, spinal column, the lungs, and 
they have even been found in the brain. They are 
given off from the body in the excrement and in the 
urine. The characteristic symptoms of the fever are 
an increasing temperature which fluctuates rather regu¬ 
larly, and rose rash over the abdomen, diarrhea or 
constipation, distention of the intestines, emaciation, 
and sometimes intestinal hemorrhages and delirium. 
The average period is four or five weeks, and this 
is followed by a long period of convalescence. Re¬ 
lapses are frequent and are dangerous and may cause 
death. Fatal cases before a relapse usually terminate 
during the fourth or fifth week. 
Typhoid is thus a parasitic disease, and its onset 
depends upon the introduction into the system of the 
typhoid bacillus. Its presence in the human body is 
