476 STUDIES IN IMMUNITY. 



appeared at that time. This description, indeed, agrees perfectly 

 with our own. We found as well as these authors that this organ- 

 ism was present in large numbers in almost pure culture (with the 

 exception of a few pneumococci) in the pus of the smaller bronchi 

 at an autopsy of a child who died of bronchopneumonia following 

 whooping-cough. Such facts evidently seemed significant. 



In studying this problem, we naturally had to compare this 

 bacillus as it appeared in our cultures, or in the newer cases which 

 we had, very carefully as regards morphology, with the organism 

 which we found in our first case in 1900 and which seemed in- 

 contestably to be the true parasite. Such a comparison, however, 

 did not settle our doubt. This latter organism evidently belongs in 

 the group of small bacteria that stain poorly, as well as the influ- 

 enza bacillus which has already been cultivated. The appearance 

 of the two organisms is not, however, identical. If we consider 

 the bacteria that we found in the exudate in 1900 as typical, they 

 are of more regularly ovoid form, and, as a general rule, somewhat 

 larger and with a more constant deeply stained center. Might 

 it not, however, seem reasonable that a given bacillus in an arti- 

 ficial medium should not appear identical with one observed in a 

 pathological specimen? In short, the two bacteria might be con- 

 sidered identical, and the opinion that a bacillus similar to the 

 influenza bacillus has an etiological function might well be accepted, 

 particularly when it has been claimed by the bacteriologists to 

 whom reference has been made. 



There are three grave objections, however, to this hypothesis. 

 In the first place the bacillus in the typical exudate of 1900 did 

 not grow in blood agar, in which medium the influenza bacillus 

 would certainly have grown readily. Then we have not been able 

 to demonstrate any particular properties against this latter organ- 

 ism in the serum of children that have recovered from whooping- 

 cough, in spite of repeated attempts. Other bacteriologists 

 must also have obtained similar negative results, for no mention is 

 made in the work of Spengler, of Jochmann and Krause and others, 

 of specific properties in the blood of recovered children. And 

 finally we found that this organism was present not only in whoop- 

 ing-cough, but also in the various respiratory affections in the 

 adult as well as in children, in cases of grippe, bronchitis and 



