5(3 LOCAL TLSSUE REAC'IIVITY 



ACriNl I'KINCIPLF.S OF ANAKROIilC: (.RAM-NEGATIVE BACILLI 

 ISOLATED EKO.M CIIKOMC I.LNG ABSCESSES 



Cohen (i()^'52, 19,^5.^5) sLiidicd extensively the anaerobic flora of 

 abscesses oi the lung. He isolated from the lesions gram-negative 

 anaerobic bacilli which were classified for convenience into the 

 chromogenic and non-chromogenic grcnips. An example of the 

 chromogenic anaerobic group is Bacleriiini nielaninogenicum, a 

 gram negative anaercjbic bacillus ^vhich produces a black, amor- 

 phous pigment on the surface of the blood agar. The non-chromo- 

 genic group of gram-negative anaerobic bacilli may be further 

 divided into Subgroup A, including organisms which liquefy gela- 

 tin (B. tJieoluidcs is an example of this subgroujj) ; and Subgroup 

 B, including cjrganisms \\hich dcj not licjuefy gelatin [B. fincusiis 

 is an example of this subgrou])) . The following method was con- 

 sidered by Cohen as optimiun for the j)r()duction of active prin- 

 ciples: 



To 4 per cent gelatin broth were added 0.1 per cent dextrose 

 and 0.5 per cent sodiinn chloride. The reaction ^vas adjusted to 

 pH 8.2. The medium was autoclaved for 15 minutes at 10 lbs. 

 pressine. The final reaction ^vas about ])H 8.0. 



For the growth of the anaerobic organisms, the following pro- 

 cedure was adopted. About from 10 to 15 c.c. of blood agar was 

 poured into a 250 c.c. flask and allowed to solidify in the re- 

 frigerator. Gelatin broth, freshly boiled and then rapidly cooled, 

 was j3oured over the blood agar in the flask until the latter was 

 two-thirds full. The gelatin broth was then allowed to congeal 

 in the refrigerator. Then from 10 to 15 c.c. of blood agar was 

 jjoured on top of the congealed gelatin. The medium thus pre- 

 pared ccjntained gelatin broth bet\veen t^vo layers of solid blood 

 agar. The flask was stored in the refrigerator. 



Before use, the medium was warmed in the incubator for about 

 twenty minutes; it ^vas then inoculated with a suitable culture, 

 sealed ^vith petrolatum and incubated at 37° c. for from two to 

 three days. 



The fluid cultures ^vere poured into flasks and centrifugated, 

 and the supernatant fltiid was filtered through a Berkefeld "V" 

 candle. A drop of the sediment \vas spread on a blood agar plate 

 and incubated aerobically, to rule out aerobic contamination. 



The filtrate was tested for sterility, stored in the refrigerator 



