COMMON COMMUNICABLE DISEASES. 
diately to prevent other germs which may be 
lurking about from getting into it, and it is then 
allowed to dry. A little of the boullion, or other 
substance, in which the bacillus typhosus is be¬ 
ing cultivated is then placed on another clean 
glass slide and covered. The dried blood of 
the suspected patient is made into a watery solu¬ 
tion and added to the culture. From this mix¬ 
ture of dried blood and typhoid bacillus, what 
is known as a “hanging drop” preparation is 
made under the microscope. If the patient has 
typhoid fever the bacilli will be seen rapidly to 
lose their power of motion and to form into 
tangled clumps, or masses, and so get 
away from the blood serum of the patient. If 
typhoid fever does not exist, this clumping and 
entanglement of the bacilli and arrest of their 
movements does not occur. There is said to be 
an exception to this rule in cases where the 
patient has had the disease recently, under 
which circumstance the reaction may occur 
without such evidence of the onset of a new 
attack. 
Cholera is caused by Koch’s comma bacil¬ 
lus. Dysentery, a somewhat similar disease, is 
caused by the bacillus dysenteriae—both of these 
diseases are contracted through the same sources 
as typhoid fever is contracted, and the same 
watchfulness against its spread must be rigidly 
carried out; also the same precautions as to per¬ 
sonal cleanliness and neatness with regard to the 
nurse, patient, and patient’s room. Be especially 
*German authorities spell this scientists name Vidal, 
and assert that he is French and that the American 
spelling, “Widal,” has arisen because of the German 
pronunciation of the letter V. 
49 
Exception to 
*Widal’s Test. 
Cholera and 
Dysentery. 
