THE PARATYPHOID GROUP 385 
in performing the agglutination test for these organisms. The ])ara- 
typhoid baciUi and B. typhosus possess in common group agghitinins 
which greatly vitiate the value of the test. The same objection does 
not hold for the diagnosis of typhoid fe^•er by the agglutination reac- 
tion however. 
The isolation of B. paratyphosus (alpha or beta) from the blood 
stream during life, or from the internal organs at autopsy is the most 
reliable method of diagnosis. Carriers are not uncommon, and like 
typhoid bacillus carriers the organisms frequently remain in the 
gall-bladder, consequently isolation of the bacilli from feces does not 
necessarily establish a correct clinical diagnosis. Paratyphoid bacilli 
have been isolated occasionally from gall stones and from cases of 
cholecystitis, particularly in women. 
SUMMARY. 
The More Important Differential Details of Paratyphoid Fever and 
OF Meat Poisoning. 
Meat poisoning. Paratyphoid fever. 
Organism Hog cholera bacillus B. paratyphosus alpha. 
B. enteritidis B. paratyphosus beta. 
Habitat of organism . Intestinal canal of lower ani- Chiefly intestinal tract 
mals chiefly: hog cholera of man. 
in swine, enteritidis com- 
mon in rodents 
Mode of infection . . . Usually contaminated meat Usually human bacillus 
(human carriers rare) carriers. 
Incubation period Six to forty-eight hours Eight to twenty days. 
Symptoms Choleraic Typhoidal. 
Pneumonic Injection ivith B. Psittacosis.— B. psittacosis causes a 
fatal enteritis in parrots, and it has been noticed, particularly in 
France, that coincidently with enteric disease in parrots a pneumonic 
infection has appeared in those associated with them.' The disease 
in man presents no definite clinical features which would differentiate 
it from typhoid fever complicated by pneumonia. The incubation 
period Aaries from five days to three weeks, usually, however, less 
than ten days. The onset is gradual in some cases, like typhoid, but 
it may be abrupt with an initial chill, as in pneumonia. The spleen 
is enlarged, but rose spots are rarely found. The mortality varies; 
it may be as high as 30 per cent. The postmortem lesions have not 
been established. In one case the bacillus was isolated from the 
heart's blood postmortem. Specific agglutinins in the patient's blood 
serum have not been satisfactorily studied, and the disease as a clinical 
entity is yet to be defined. The principal evidence of the causative 
relationship of B. psittacosis to the disease rests at present upon the 
occasional household ei)idemics following closely upon the presence of 
a diseased parrot. 
' Manningei : Ueber eine durch Bacillus paratyphi beta vcrursachte Infecktionskrank- 
heit der Feriken, Centralbl. f. Bakteriol., orig., 1913, 70, 12. 
25 
