ALLIED BACILLI. 331 



(Gaertner), the so-called paracolon bacillus, and the bacillus of 

 psittacosis may be described. 



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

 number of cases of illness resulting from eating the flesh of a diseased cow, 

 isolated, not only from the meat but from the spleen of a man who died, a 

 bacillus which presents all the characteristics of the B. typhosus except that it 

 ferments dextrose and is very pathogenic to animals. In the latter, whatever 

 the method of introduction, there is an intense haemorrhagic enteritis with 

 swelling of the lymph follicles. The distribution of the bacilli varies in different 

 cases, but usually they are present in the solid organs. In man also the symp- 

 toms are centred in the intestine, and hence the name given to the bacillus. 

 During recovery a very characteristic point is the occurrence of desquamation 

 of the epidermis. Since it was described by Gaertner others have isolated the 

 bacillus under similar circumstances. Its toxic products have been found to be 

 very pathogenic to -animals, and in man cases of illness have occurred when 

 broth made from the diseased flesh has been partaken of. When there is an 

 infection by the bacillus itself, symptoms usually begin after twenty-four hours. 

 Many cases, however, of an earlier illness have occurred, no doubt due to the 

 action of toxins already existing in the meat. During the last few years, in some 

 epidemics of meat-poisoning, similar bacilli differing slightly from Gaertner's 

 bacillus have been isolated, e.g. by Durham, and it is probable that here also 

 we have to do not with one variety but with a group of bacilli, probably of 

 the same species and possessing more or less similar pathogenic properties. 



The Paracolon (Paratyphoid) Bacillus. Under the names paracolon or 

 paratyphoid bacillus, Widal, Gwyn, Schottmuller, and others in Europe and 

 America, have described bacilli associated with continued fevers, whose clinical 

 features were identical with those of typhoid fever, but in none of which could 

 the presence of B. typhosus be positively determined by either blood reaction 

 or by cultural means. Morphologically, these bacilli resemble B. typhosus 

 closely, but may be readily differentiated from it both culturally and by serum 

 reaction. They ferment glucose, but not lactose or saccharose ; litmus milk 

 at first strikes a mild acid reaction, with a blue-green cream-ring, but about 

 the fourth or fifth day gradually loses this acidity and slowly becomes alkaline, 

 with no coagulative phenomena; the potato growth is usually like that of B. 

 coli, but may be at times almost invisible ; the production of indol is incon- 

 stant. Typhoid sera fail to agglutinate paracolon bacilli, and vice versa, 

 paracolon sera never clump B. typhosus; and further, the serum from one 

 paracolon infection may not be able to agglutinate the bacilli derived from 

 another. From B. coli they are easily distinguished by their fermentative 

 reactions and by their behaviour in litmus milk. Their position is undoubtedly 

 in that group designated by Durham, in his interesting study of colon bacillus 

 and allied forms, as the B. enteritidis group. 



The Psittacosis Bacillus. When parrots are imported from the tropics in 

 large numbers many die of a septicaemic condition in which an enteritis, it may 

 be haemorrhagic, is a marked feature. There is intense congestion of all 

 the organs and peritoneal ecchymoses. From the spleen, bone marrow, and 

 blood there has been isolated a short actively motile bacillus with rounded 



