THE MICROBES OF HUMAN DISEASES. 209 
has carried a liquid containing dangerous microbes 
straight into the intestines. Indigestion, and catarrh 
of the stomach and intestines, of which diarrhcea is 
a symptom, constitute predisposing causes of the 
disease. . 
Among other substances unfavourable to the de- 
velopment of the microbe, and thus constituting a 
preventive of cholera up to a certain stage, we may 
mention calcium sulphate, which acts by producing 
sulphuretted hydrogen gas, also carbolic acid, salicylic 
acid, thymol, alcohol, acetic acid or vinegar, and 
mustard oil, which, like the other volatile substances 
already mentioned, constitutes an excellent antiseptic 
in an epidemic of cholera. 
We shall speak in another chapter of the purity 
of drinking-water, which is of great importance, and 
of the improved filters invented to eliminate the 
microbes which are not arrested by ordinary filters. 
IX. THe EXANTHEMATA: SCARLATINA, SMALL-POX, 
MEASLES, VACCINIA. 
Microbes are found in the eruptions characteristic 
of all these diseases. They are generally micrococci, 
isolated or in chaplets. ; 
Measles.—Babés, in 1880, was the first to describe 
the micrococci which he observed in this disease, and 
especially in the pneumonia by which it is often com- 
