A STUDY OF CERTAIN PYOGENIC BACTERIA 73 



EXERCISE XXIV 



A STUDY OF CERTAIN PYOGENIC BACTERIA 



108. There are a number of bacteria which are able to 

 cause suppuration, but ordinarily the formation of pus is due 

 to the presence of certain streptococci and micrococci. A 

 number of bacilli, especially B. coli communis and Ps. pyocy- 

 aneus, are frequently found as the apparent cause of suppura- 

 tion. As it is impossible to study more than a very few of these 

 species, two of the most common and one of the more rarely 

 encountered organisms in suppurating wounds and abscesses 

 are chosen for special study. 



References. Chapters on pyogenic bacteria in text and refer- 

 ence books. Christman (recherches sur la suppuration), Annals 

 de rinst. Pasteur, Vol. II (1888), p. 469. Lucet (in animals), Ibid., 

 Vol. VII (1893), p. 325. Von Lingelsheim (concerning strepto- 

 cocci), Zeitschrift fiir Hygiene, Bd. X (1892), S. 331. Moore, Am. 

 Vet. Review, January, February-, and March, igoo. 



109. Work for this exercise. Inoculate a tube of each 

 medium in Groups A and B from each of the cultures of 

 Streptococcus pyogenes and Micrococcus pyogenes aureus which 

 will be furnished. 



Describe the cultures of Ps . flicorescens liquefaciens and ex- 

 amine the bouillon culture microscopically in a hanging-drop 

 and in a stained preparation. 



Examine the milk and gelatin cultures made from the 

 colonies from milk and water plates. 



Read carefully the chapter on pyogenic bacteria in the 

 text-books. 



Give in the notes a definition of each of the following terms : 

 saprophytic, parasitic, pathogenic, and pyogenic bacteria. See 

 text-books. 



