432 PATHOGENIC MICROORGANISMS 



genie saprophyte. Recently Krumwiede, Pratt, and Kohm have shown 

 that the members of this group and some of the so-called paratyphoid 

 C group may be distinguished from all the other paratyphoids by 

 inability to ferment xylose, and Weiss has shown paratyphoid A may 

 be subdivided on the basis of antigenic properties. 



Type B grows more heavily on all media than A, especially on 

 potato (though this is irregular). Milk is slightly acidified at first, 

 but eventually is rendered alkaline and cleared, possibly by casein 

 solution. 



Subdivision of this group was made by Weiss and others on the 

 basis of inosite fermentation. Eventual differentiation must be made 

 by agglutination. 



The diseases caused by these bacteria may be divided as follows : 



I. Those which fall into the category of meat poisoning with sudden 

 onset of gastroenteric symptoms following ingestion of meat; and 



II. Those in which the disease simulates a mild typhoid fever, dif- 

 fering from tftis only by the absence of the specific agglutination. 



The differential diagnosis between the second type of case and true 

 typhoid fever may be extremely difficult. In contradistinction to 

 true typhoid the temperature reaction of this case may set in more 

 abruptly and remain more irregular throughout the disease. Gastric 

 symptoms, vomiting, and nausea are often more prominent than in 

 typhoid fever and enlargement of the spleen is less regularly 

 present. Owing to the low mortality of paratyphoid fever (in 

 120 cases observed by Lentz * less than 4 per cent, and in many 

 other smaller epidemics no deaths have occurred), we have remained 

 relatively ignorant concerning the pathologic anatomy of the dis- 

 ease. Longcope 2 observed a case, fatal after two weeks of illness, 

 in which there was no enlargement of Peyer 's patches and no sign of 

 even beginning ulceration. Most other observers have also found less 

 involvement of the lymphatics of the bowel than is found in typhoid 

 fever. During the disease the bacteria can often be cultivated from 

 the blood, and the serum of the patient may agglutinate specifically 

 paratyphoid strains. In this way the diagnosis can often be made. 

 Libmann 3 has isolated the organism from the fluid aspirated from the 

 gall bladder in a case operated on for cholecystitis. 



Most of these microorganisms possess pathogenicity for mice, guinea- 



1 Lentz, Klin. Jahrb., xiv, 1914. 



2 Longcope, Amer. Jour, of Med. Sciences, cxxiv, 1902. 



3 Libmann, Jour, of Med. Res., viii, 1902. 



