430 THE PARATYPHOID A. BACILLUS 



the serum. Grattan and Wood say : " before accepting a suspected 

 organism we require that it shall completely remove the agglutinin specific 

 for the paratyphoid A bacillus. As controls we have frequently tested 

 heterologous organisms such as the typhoid, paratyphoid B and colon bacilli 

 against our paratyphoid A serum but have never removed the agglutinin 

 specific for the paratyphoid A bacillus." 



3. The reactions of the serum of patients suffering from paratyphoid A 

 fever have been described above. 



The pseudo-paratyphoid A bacillus. 



This organism appears to be a common inhabitant of the intestines of pigs (Mor- 

 gan) and has once been isolated from the human subject during some investigations 

 on the cause of summer diarrhoea (Morgan). 



The pseudo-paratyphoid A bacillus is culturally identical with the paratyphoid 

 A bacillus but differs from the latter in that it is not agglutinated by a specific 

 paratyphoid A serum. 



