THE MICROBES OF HUMAN DISEASES. 209 



has carried a liquid containing dangerous microlDes 

 straight iato the intestines. Indigestion, and catarrh 

 of the stomach and intestines, of which diarrhoea 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. — Babes, 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- 



