THE GAERTNER BACILLUS 



443 



carcase of a guinea-pig killed with a dose of living virulent culture died in 

 8-15 days when the meat was given uncooked, and in 30-38 days when the 

 meat was boiled before being given to them (Cathcart). 



SECTION II. MORPHOLOGY. 



In its microscopical appearances and staining reactions the gaertner bacillus 

 is indistinguishable from the other members of the typhoid-colon group. 



On the ordinary media it grows readily yielding growths which are in no 

 way different from those of the paratyphoid B bacillus and of the aertrycke 

 bacillus. 



SECTION III. BIOLOGICAL PROPERTIES. 



1. Biochemical reactions, (a) Action on carbohydrates. The fermentation 

 reactions of the gaertner bacillus are identical with those of the paratyphoid 

 B and aertrycke bacilli. 



(/3) Production of indol. Gaertner's bacillus produces no indol when 

 grown in peptone water. 



2. Toxin. The gaertner bacillus contains a toxin of the endotoxin type 

 (Cathcart). The most powerful toxin is obtained by washing off the bacilli 

 from an agar culture in a Roux bottle with distilled water or normal saline 

 solution, adding a little toluol, allowing to autolyze for 8-10 days the 

 bottles being repeatedly shaken during this process and then sterilizing by 

 heat (60-100C. for 30 minutes). Heated extracts are more toxic than 

 unheated, and the toxin produced in this manner will withstand a tempera- 

 ture of 100 C. for 30 minutes. 



Autolyzed bacilli heated for 30 minutes at 60 C. are fatal to guinea-pigs 

 and mice in 24-48 hours when inoculated intra-peritoneally in doses of O'l c.c. 

 The symptoms following the inoculation of toxin are very definite, the most 

 notable being the glueing together of the eyelids and the prolonged (up to 

 9 hours) narcosis preceding death. Post mortem, there is hyperaemia of the 

 lungs, spleen, supra-renals, etc., and frequently small necrotic areas in the liver. 



3. Agglutination. The serum of persons suffering from an infection with the 

 gaertner bacillus, and the serum of animals immunized by repeated inoculation 

 of small sub-lethal doses of the organism, have the property of agglutinating it. 



In cases of human infection the limits of agglutination are about 1-250 

 to 11000. Human serums have no action, or, at most, a negligible effect, 

 on the paratyphoid B and aertrycke bacilli. 



The serum of immunized animals will agglutinate the gaertner bacillus 

 when diluted as much as 50,000 times, but it has only a very slight action 

 on the paratyphoid B and aertrycke bacilli : it is therefore a simple matter 

 to distinguish paratyphoid B and aertrycke on the one hand from gaertner 

 on the other. These facts may be illustrated by the subjoined table extracted 

 from Bainbridge (Jr. Path, and Bact. xiii. p. 452). 



