249 



8. In military camps and barracks Pfeiffer's bacillus was 

 encountered in distinctly wider distribution than was usual 

 in the remainder of the population. 



9. Pfeiffer's bacillus was found a little more commonly in 

 persons who had had influenza than in others, but it may also 

 occur in wide distribution among the latter. 



From numbers 1, 7, and 9 it is concluded that its distri- 

 bution in influenza was secondary to the influenza and that 

 its distribution in healthy subjects was probably secondary 

 to its occurrence in influenza. 



10. In inoculations from the mouths of 60 guinea-pigs 

 Pfeiffer's bacillus was found in 5. It could not however be 

 demonstrated in horses or mice. 



11. From the different sources named about 800 strains 

 were cultivated. In all of these (with unimportant exceptions) 

 the characters detailed below under a, d, g, h, and either e, 

 or f, were demonstrated. The other characters were identified 

 in a smaller number, in most cases in about 150 strains. As 

 these may practically be looked upon as random samples of 

 the entire material it is justifiable to assume that the charac- 

 ters which were demonstrated only in these strains were com- 

 mon to the whole material and to the complete flora of Pfeif- 

 fer's bacilli present in Denmark. 



(a). Microscopically they were all rods which could 

 however assume very different forms. The collection of forms for 

 the whole group is very large (see plate 3), but not unlimited. 

 The most important common feature is the slenderness of the 

 bacilli, at least in a number of the individuals in a culture. 



The collection of forms of an individual strain often con- 

 stitutes a considerable proportion of the forms of the whole 

 group. 



(b). They are non-motile. 



(c). Spores can never be demonstrated. 



(d). They are distinctly Gram negative. 



(e). In pure culture they cannot grow on ordinary peptone 

 broth agar. 



(f). In pure culture they are usually unable to grow on 

 blood-free ascitic agar. Very occasionally however a slight 

 growth is observed. 



(g). For a rich growth red blood cells or certain of their 



