Io6 LABORATORY GUIDE IN BACTERIOLOGY 



COCCUS pyogenes. These organisms are pathogenic, 

 and care must be taken to observe the rules of technic. 

 Any carelessness may be followed by grave conse- 

 quences. In case of accident, such as the spilling of a 

 culture or infecting of the hands, disinfection — e.g., 

 with a solution of mercuric chlorid (i:i,ooo)^s neces- 

 sary. 



After 24 hours' incubation of three agar slants, 

 proceed with the other media as outUned in the routine 

 study (pp. 50 £f.). 



Special study. — Inoculate a rabbit intravenously 

 with a broth culture of Staph, aureus. The ear of the 

 rabbit is shaved, and washed with mercuric chlorid 

 solution, followed by alcohol. Then i or 2 c.c. of a 

 24-hour-old culture in broth is drawn up into a h3rpo- 

 dermic syringe, which has been sterilized by immersion 

 in boiling water for 10 minutes. 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 hold the fore-legs. If the 

 animal struggles, force should not be applied, as this 

 might cause injury. The struggles may be overcome 

 by wrapping the animal in a towel or some other piece 

 of cloth. The needle is then inserted into the lumen 

 of the lower vein (ramus lateralis posterior of the vena 

 auricularis posterior), which has been pinched between 

 the fingers, or by means of a forceps, so as to arrest 

 the circulation. No air should be injected with the 

 culture, as this will kill the animal. The hypodermic 

 syringe is then withdrawn and sterilized in boiling 

 water for 15 minutes. 



