The Oidia 



45 



They are common micro-organisms of the air and appear as 

 frequent causes of contamination in culture-media, upon all 



Fig. 8. Oidium, showing the various vegetative and reproductive ele- 

 ments. X 350 (Grawitz). 



forms of which they grow readily, producing liquefaction 

 where possible. They engage in but few pathogenic processes, 

 the most familiar being that brought about by Oidium albi- 



Fig. 9. Oidium (Kolle and Wassermann). 



cans, which causes the common disease of childhood known as 

 thrush (q. v.). 



