TECHNIC OF BACTERIOLYTTC TESTS 



369 



process of drying the amboceptor content may be decreased. Dried 

 serum is to be preferred, however, as it keeps much longer and there is 

 no danger of rendering it worthless by contamination. After drying, 

 the product is ground in a mortar and stored in amounts of 0.1 or 0.2 

 gram in separate ampules. 



In determining the bacteriolytic titer of dried serum 0.1 gram is 

 carefully weighed out and dissolved in 9.9 c.c. of sterile bouillon. From 

 this stock dilution other dilutions may be prepared, in the manner pre- 

 viously described, and injected with a loopful of the culture. 



FIG. 100. CULTURE OF CHOLERA UN- 

 DERGOING BACTERIOLYSIS. A POSI- 

 TIVE PFEIFFER REACTION. 



A hanging drop of peritoneal exudate 

 removed from a guinea-pig one-half hour 

 after injection with 1 c.c. of the suspension 

 shown in Fig. 101 with 1 c.c. of 1 : 1000 

 dilution of cholera immune serum. Note 

 that the bacilli are now quite short and 

 coccoid in shape. At the end of seventy 

 minutes the exudate was sterile. What 

 appears to be two or three coccoid forms 

 in apposition is really one bacillus under- 

 going lysis. 



FIG. 101. CULTURE OF CHOLERA BE- 

 FORE BACTERIOLYSIS. X 720. 

 A hanging drop of cholera in normal 

 salt solution prepared from a twenty- 

 four-hour culture of cholera on agar- 

 agar. 



After securing an immune 

 serum of satisfactory potency the 

 main test may be conducted. 

 While the technic is more difficult 

 than that of agglutination tests, 



the results, under proper conditions, are more conclusive, for there is 

 less likelihood of group or partial amboceptor activity for closely allied 

 bacteria taking place. 



Technic of the Pfeiffer Test. The suspected culture to be tested 

 should be grown on agar for from eighteen to twenty-four hours, and 

 used in doses of one loopful (2 mg.). 



If cholera is suspected, cholera immune serum of known titer should 

 be used. Dilutions of serum are made with sterile bouillon, and 2 c.c. 

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