VI 



living as harmless saprophytes on the mueous membranes of 

 normal and apparently quite healthy persons. Both, also, are 

 intimately associated with " colds " and inflammatory conditions 

 though with this difference that the pathogenic role of the 

 pneumoooeous ta accepted, whereas the pathogenicity of Pfeiffer's 

 bacillus as a primary agent of infection is still sub judice. It is 

 of particular interest to note that Dr. Scott has found Pfeiffer's 

 bacillus to be frequently associated with the pneumococcus in 

 cases of pneumonia. It is not yet possible to decide whether, 

 in cases such as these, the bacillus prepared the way for the 

 coccus or the coccus for the bacillus ; but, in either event, as 

 Pfeiffer's bacillus is known to be toxic, its presence in the tissues 

 cannot be regarded as innocuous. Serologically, both the 

 pneumococcus and Pfeiffer's bacillus form an indefinitely large 

 number of different races; but with the latter organism the 

 differences are not so sharply defined as with the pneumococcus, 

 and there is not the definite association of particular serological 

 types with morbid processes which is found with pneumococci 

 of Types I and II. Like most cautious bacteriologists, Dr. Scott 

 concludes that the plea for Pfeiffer's bacillus as the cause of 

 influenza is neither proved nor disproved. Probably it will 

 take some years before this question is settled. But quite 

 apart from the etiology of influenza, the study of Pfeiffer's 

 bacillus is important because it appears to be one of the 

 organisms which are liable to change suddenly from the 

 saprophytic to the parasitic mode of existence and then to 

 be associated with inflammatory conditions of the respiratory 

 tract and other regions. 



1 have the honour to be, 



Sir, 



Your obedient Servant, 



GEORGE NEWMAN 

 Whitehall, 



July, 1922. 



