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 



