BACILLUS EXTERITIDIS 383 



against Gaertner's bacillus or the bacillus of psittacosis are used. 

 In all serum tests the essential point is that deductions should 

 only be based on comparative observations of the highest 

 dilutions in which a clumping effect is produced with any series 

 of organisms compared. 



While the paratyphoid bacillus originates a disease resembling 

 typhoid fever, it has also been found in the stools of typhoid 

 patients, and mixed infections may thus occur. Both organisms 

 have been observed together in the stools in typhoid carriers, and 

 pure paratyphoid carriers are also stated to occur. A meat 

 poisoning epidemic attributed to the paratyphoid bacillus has 

 been reported. Besides the septic cases already alluded to, the 

 organism has been isolated from cases of bone abscess, from 

 orchitis, and in Widal's case from a thyroid abscess, and in such 

 cases the history of a previous typhoid-like illness may not be 

 elicited. It has also been found in ordinary faeces. In animal 

 experiments it produces in rabbits and guinea-pigs a fatal illness 

 of a septictemic type with serous inflammations. 



Bacillus Enteritidis (Gaertner). In 1888, Gaertner, in 

 investigating a number of cases of gastro-enteritis resulting from 

 eating the flesh of a diseased cow, isolated, from the meat and 

 from the spleen of a man who died, a bacillus closely resem- 

 bling the typhoid bacillus. Since then, in a great number of 

 similar outbreaks, similar bacilli have been found both in the 

 stools and in the organs. The cultural characters are those of 

 the group, except that in some strains the presence of an effect on 

 lactose has been observed. Here again much information may 

 be obtained from the agglutinating properties of the serum. 

 It has also been found that the serum of persons suffering from 

 meat poisoning sometimes clumps the typhoid bacillus, though 

 a higher concentration is required than in the case of Gaertner's 

 bacillus. The Gaertner group of organisms is very pathogenic 

 for laboratory animals. Often, whatever the channel of infec- 

 tion, there is intense haemorrhagic enteritis, and very usually 

 there is a septicaemia with the occurrence of serous inflammations ; 

 the bacilli are recoverable from the solid organs and often from 

 the blood. In man, as the name of the bacillus indicates, the 

 symptoms are centred in the intestine, where there is usually 

 marked inflammation of the mucous membrane, sometimes 

 attended with haemorrhage into it ; evidence of a septicaemic 

 condition may also exist. Infection may take place by the 

 bacillus itself, and here the illness usually appears within 

 twenty-four hours of the food being partaken of, but symptoms 

 may appear almost at once, in which case they are no doubt due 



