THE GARTNER GROUP 443 



B. aertrycke seems to be identical, or almost so, with the B. snipes- 

 tifer. 



Several races of B. aertrycke seem to exist which can be differen- 

 tiated only by absorption tests, and even in these it may be 

 necessary to absorb not only Y serum with X bacillus, but also 

 X serum with Y bacillus, in order to establish dissimilarity. By 

 these means, according to Schiitze, the following types may be 

 distinguished : 



1. Mutton type. From mutton in a food-poisoning outbreak in 

 Newcastle in 1911, and elsewhere. 



2. Hirschfeld type. Hirschfeld's para C, from cases of enteric- 

 like fever, Salonika, Baghdad, and elsewhere. 



3. Newport type. Case of food-poisoning, Newport. 



4. Stanley type. From case of food-poisoning. 



Also 5. Binns, 6. Arkansas, 7. G., and 8. Reading, types. 



The Mutton group is by far the commonest, and all give rise to 

 gastro -enteritis. It includes strains from various countries, and 

 from animal as well as human epidemics. 



The Hirschfeld group has been met with only in the East, and 

 causes enteric -like infections. 



The B. icteroides was isolated by Sanarelli from cases of yellow 

 fever, and for a time was regarded as the causative organism of 

 this disease, but was subsequently shown by the Americans to be 

 apparently identical with B. suipestifer, though complete sero- 

 logical proof is lacking. It is, therefore, a secondary or terminal 

 infection in yellow fever. 



Of animal diseases, the B. enteritidis is occasionally responsible 

 for extensive fatal epizootics among guinea-pigs, rats and mice. 

 It constitutes the Danysz and other viruses used for the exter- 

 mination of rats. The B. typhi murium of Loftier causes a fatal 

 epizootic among field mice, and has been used as a virus for their 

 extermination. Actually it seems to belong to at least three 

 groups (see table, p. 454). 



The B. psittacosis is the cause of a fatal epizootic among birds, 

 particularly parrots. It is transmissible to man, causing a severe 

 and often fatal broncho-pneumonia, and is met with among bird- 

 dealers, sailors, etc. Serologically, the organism appears to 

 belong to the B. aertrycke, Mutton group. 1 



1 H. M. Perry, Brit. Journ. Exper. PathoL, vol. i, 1920, p. 131. 



