THE BACILLUS OF INFLUENZA. 371 



The lesion consisted mainly of an inflammatory exuda- 

 tion that had undergone caseation, but in addition there 

 were present isolated nodules that in size and general 

 appearance were difficult to distinguish from miliary 

 tubercles. Giant cells were not seen. The streptothrix 

 was abundant in the lung, appearing as masses of con- 

 voluted, branching threads. The contours of the rods 

 were not quite uniform, the staining was irregular, and 

 occasionally a thread was seen that, toward its extrem- 

 ity, appeared to be breaking up into short segments. 

 No coccus-like forms were seen. It is stained best by 

 the Weigert method, when deeply stained masses sepa- 

 rated from one another by more or less clear spaces are 

 to be detected. The organism was not obtained in 

 culture, and no effect was produced on guinea-pigs 

 by subcutaneous inoculation with bits of the diseased 

 lung.^ 



THE BACILLUS OF LNFLUENZA. 



An important historic epidemic disease, on the nature 

 of which much light has been shed through modern 

 methods of investigation, is influenza. Quoting Hirsch, 

 the first trustworthy literary records that we have of 

 this disease date from the early part of the twelfth 

 century. 



Between 1173 and 1874 it made its epidemic or pan- 

 demic appearance on eighty-six difierent occasions. Its 

 first appearance in this country was in Massachusetts in 



1 For the literature on pathogenic streptothrices, see Flexner : 

 Journal of Experimental Medicine, 1898, vol. iii. p. 435 ; for a sum- 

 mary of cases in which streptothrices have been found, see Muaser, 

 Pearce, and Gwyn : Transactions of the Association of American 

 Physicijms, 1901, vol, xvi. p. 208, 



