380 TYPHOID FEVER 



the symptoms were caused by alkaloidal substances produced 

 during putrefactive processes occurring in meat. Certain cases 

 of illness arising within an hour or two of the taking of tainted 

 meat may be due to poisons of such a kind, but in the great 

 majority of single or multiple cases of illness traceable to food, 

 the symptoms do not appear so rapidly, and are associated with 

 the multiplication in the intestine of organisms of the type now 

 under consideration, and it may be also with an infection of the 

 blood. In such cases, the meat at fault may not, to taste or 

 smell, present any unusual features, but very often there can be 

 isolated from it an organism identical with organisms derived 

 from the sick individuals. Sometimes it has been proved that 

 the animals from which the meat was derived have been suffer- 

 ing from illnesses probably due to the organisms subsequently 

 found, but this has not always been the case, healthy meat being 

 here contaminated by contact with infective matter. The foods 

 giving rise to poisoning usually belong to the preserved food 

 class, or consist of sausages or similar products. There is every 

 reason to believe that the organisms in question may not be 

 killed in the ordinary processes of cooking, in which the internal 

 parts of the meat may not reach the temperature of blood 

 coagulation. 



The organisms included in the paratyphoid and food-poisoning 

 group are as follows : The paratyphoid bacillus, varieties A and 

 B, originally isolated from pathological conditions in man ; 

 bacillus enteriditis Gaertner, isolated from meat-poisoning cases ; 

 bacillus ^Ertryck, also isolated from meat poisoning; bacillus 

 suipestifer (Salmon's bacillus of hog cholera) ; psittacosis bacillus, 

 occurring in a disease of parrots ; bacillus typhi murium, isolated 

 by Loffler from an epidemic of enteritis in mice ; and Danysz's 

 bacillus, isolated from an epidemic in field mice, and used by 

 him for originating epidemics in rats. The pathological effects 

 produced by these organisms include, on the one hand, general 

 septicsemic manifestations, and, on the other, gastro-enteritis. 

 The chief members of the group will be described below. 



The Characters of the Paratyphoid and Food-Poisoning 

 Bacilli. These bacilli are all miscroscopically indistinguish- 

 able from the bacillus typhosus. They are Gram-negative, 

 motile bacilli, the flagella being sometimes few in number, and 

 they do not form spores. On ordinary media, growths have the 

 general character of those of the b. coli and b. typhosus, some 

 members in certain reactions resembling the one, and in others 

 resembling the other. Opinion differs as to their capacity to 

 form indol, but usually the reaction to this test is negative. 



