PATHOGENIC BACTERIA. 121 



other organisms by carbolic acid. An epidemic has been traced 

 to the eating of oysters taken from contaminated water. 



Persistence in Water. Franckland kept bacilli alive in water, 

 sterilized by heat, 75 days ; in filtered water at 19 C., 5 days ; 

 at 6 C., 12 days. In ordinary water they are likely to be de- 

 stroyed in a few days by the overgrowth of other bacteria. 



Products. Brieger found a ptomaine in the cultures which he 

 named typhotoxin with the formula C 9 H 17 NO 2 . It has no 

 specific action. A toxalbumen insoluble in water has also been 

 isolated, but, as experiment animals are immune to the disease, 

 no definite actions have yet been determined. 



The cultures, when old, show an acid reaction. 



Paracolon or paratyphoid bacilli are members of the colon 

 group recently described by Widal, Gwyn, Schottmuller, and 

 others. They are of importance, since they produce fevers 

 clinically resembling a mild form of typhoid, and which are 

 rarely fatal. They may be the sole cause of the disease, and 

 probably also occur together with the typhoid bacillus in mixed 

 and secondary infections. Morphologically they resemble the 

 typhoid bacillus, but differ from it culturally and give their 

 own serum reactions with the blood of affected patients. They 

 ferment glucose, but not lactose or saccharose ; litmus milk at 

 first becomes acid, but later grows alkaline and is not coagu- 

 lated. On potato a slight visible growth occurs ; indol is usually 

 not formed. Typhoid sera do not agglutinate paracolon bacilli, 

 and vice versa; also different paracolon infections may not 

 agglutinate each other. The Bacillus enteritidis of Gartner is 

 a related form. 



Bacillus psittacosis is an allied form occurring in parrots, 

 and producing hemorrhagic septicemia in them and experi- 

 ment animals. The disease is readily communicated to man 

 from the affected birds, and causes, after ten days' incubation, 

 a disease, the chief symptoms of which are fever, delirium, 

 vomiting, diarrhoea, and albuminuria, about a third of the 

 cases ending fatally. The organism is agglutinated by strong 

 dilutions of typhoid serum, but the clumping is incomplete and 

 the bacillus differs further from the typhoid bacillus in its 

 growth on potato and in the nature of the infection produced. 



