PARENTERIC 



1405 



Historical. — Since the discovery of the paratyphoid bacilli 

 cases of clinical enteric, but apparently due to germs different from 

 those of the enteric group (typhoid, para A, para B), were placed on 

 record by a few observers. These cases were generally viewed 

 with much scepticism, which was to a certain extent justified, 

 as in a number of cases the germ believed to be the cause of the fever 

 represented in reality merely a secondary infection. After our 

 work, that of Balfour, and of Archibald, the fact that there is a 

 group of fevers due to so-called intermediate intestinal germs began 

 to attract more general attention, and i-s now accepted by most 

 authorities. 



Geographical Distribution. — Par enteric occurs apparently in every 

 climate, but is of much more frequent occurrence in tropical and 

 subtropical countries. Cases have been reported from Ceylon, 

 India, Egypt, the Sudan, the Balkans, Southern and Central 

 Europe. 



-ffitiology and Classification. — Par enteric is caused by a large num- 

 ber of intestinal bacteria, excluding B. typhosus, B. paratyphosus A, 

 and B. paratyphosus B. ^Etiologically one might differentiate a 

 variety of parent eric for each species of intestinal germ capable of 

 becoming the setiological agent of a fever, but such a procedure 

 would differentiate several scores of parent eric fevers, and we 

 therefore consider it simpler, for the time being, to classify par- 

 enteric according to six types, corresponding to the six principal 

 groups in our classification of intestinal bacteria (Chapter XXXVI., 

 p. 932), as follows: — 



A. Parenteric due to bacteria of genus Eberthus Castellani and 

 Chalmers, excluding B. typhosus, and of genus Alkaligenes Castellani 

 and Chalmers. 



These cases do not seem to be very rare. Among the germs found 

 we may mention B. fcecalis alkaligenes Petrewsky, B. fcBcaloides 

 Castellani, S. meta-alkaligenes Castellani, B. par a- alkaligenes Castel- 

 lani, B. vivax Archibald, B. pritnitzi Castellani, B. kandiensis 

 Castellani, etc. It would appear that these germs are usually non- 

 pathogenic, but under certain circumstances, of which very little 

 is known, may become so. 



B. Parenteric due to intestinal bacteria of genus Salmonella Lig- 

 ni^res emend. Castellani and Chalmers, apart from B. paratyphosus 

 A and B. These cases seem to be the most frequently met with. 

 Among the bacteria found we may mention B. psittacosis Nocard, 

 B. columbensis Castellani, B. archibaldi Castellani and Chalmers. 

 These three germs seem to be constantly pathogenic, while many 

 other members of the group are often non-pathogenic, representing 

 when found only secondary infections, although it is not excluded 

 that at times they may become pathogenic. 



Two very important germs of the genus Salmonella are B. aertryke 

 De Nobele ( = jB. suipestifer) and B. enteritidis Gaertner, but these two 

 germs very seldom give rise to an enteric-like fever; usually they 

 give rise to acute enteritis. 



