CHAPTER XII 

 THE PYOGENIC GROUP 



EXERCISE I. THE PYOGENIC GROUP (SUBGROUP A) 1 

 MEMBERS 



Staphylococci, streptococci, Microc. tetragenus. 



Inoculate agar-slants from cultures (furnished) of 

 Staphylococcus pyogenes aureus, Staph. pyogenes albus, 

 and Streptococcus pyogenes. These organisms are patho- 

 genic, and care must be taken to observe the rules of 

 technique with the utmost accuracy. Any carelessness 

 may be followed by the gravest consequences. In case 

 of accident, such as the spilling of a culture or infecting 

 the hands, thorough disinfection e. g., with a solution 

 of mercuric chlorid (i : 1000) is absolutely necessary. 



After 24 hours' incubation of the three agar-slants, 

 proceed with the other media as outlined in the routine 

 study (Chap. IX). 



Special study. A rabbit will be inoculated intra- 

 venously with a broth-culture of Staph. pyogenes aureus. 

 The ear of the rabbit is carefully shaved, washed with 

 mercuric chlorid solution, followed by alcohol. Then 

 0.5 c.c. of a 24-hour-old culture in broth is drawn up 

 into a hypodermic syringe, which has been previously 

 sterilized by immersion in boiling water for 10 min- 

 utes. The mode of holding a rabbit is as follows: 

 The left arm of an assistant rests against the hind- 

 quarters of the rabbit on the table, while the two hands 



1 This subdividing of the pyogenic group is an arbitrary 

 measure designed simply to facilitate study, the commoner pyo- 

 gens being studied first. 



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