450 INFECTION AND IMMUNITY. 



then, similar cases have been reported and two 

 types of the paratyphiod bacillus have been recog- 

 nized (Schottmiiller). Bacilli of Group B cause 

 first an acid reaction in milk which changes 

 to a permanently alkaline reaction in about ten 

 days, whereas those of Group A cause permanent 

 acidity (Kayser). They resemble the typhoid 

 bacillus morphologically, but culturally are more 

 closely related to Bacillus enteritidis. Organisms 

 which have previously been described as "para- 

 colon" bacilli (Widal, Gwyn) do not differ from 

 those which are now called paratyphoid bacilli, 

 and the infections caused by them resembled the 

 recorded cases of paratyphoid fever. The term 

 "paracolon" should no longer be applied to them. 

 Paratyphoid fever occurs sporadically or in epi- 

 demic form, and bears a close resemblance to mild 

 typhoid-like epidemics which have been noted from 

 time to time, and which, presumably, are caused 

 by eating poisonous meats. One such epidemic of 

 600 cases was caused in Switzerland in 1878 by 

 the meat of a sick calf; the mortality was 1 per 

 cent. A still older epidemic (1839) is cited, like- 

 wise caused by meat. In both instances the infec- 

 tion eventually was carried from person to person 

 by contact. A recent outbreak in Kiel, proved to 

 be paratyphoid, is assumed by Fischer to have been 

 caused by infected meat, on account of the peculiar 

 distribution of the cases among the patrons of a 

 particular market. Kurth also attributed a small 

 epidemic to either uncooked meat or milk. Fischer 

 mentions fifty cases in East Holstein probably 

 caused by the milk of two cows. Shortly after the 

 epidemic began, the cows died and paratyphoid 



