272 THE AMERICAN MONTHLY [Sept 



wefe in the cellar, and were cleaned only once or twice a 

 year and never disinfected. Under these conditions an 

 outbreak of diphtheria among the children appears to 

 have been brought about by this material in the cellar 

 becoming infected perhaps by particles of partly dried 

 mucus containing the bacillus being carried down through 

 the ventilating flues which were built so as to pass 

 through these vaults. Infection once accomplished pro- 

 pagation of the bacillus on a large scale would ensue on 

 the plan of plate cultures, there being accessions of fresh 

 material suitable for the purpose daily. This being the 

 case it would need only some failure of the ventilating 

 apparatus to allow the vapors arising to find their way 

 into the rooms most distant from the main ventilating 

 shaft and it was in these rooms precisely that the disease 

 occurred and spread. An effort was made in this case to 

 secure cultures, but the difficulty was that the bacterial 

 flora was too abundant, and the particular bacillus sought 

 was lost in the crowd, as in other experiments of the 

 kind with drain pipes and receptacles having the pecu- 

 liarities indicated. 



A very important point in connection with such preva- 

 lence of diphtheria as has just been indicated, is the oc- 

 currence simultaneously of much ordinary sore throat so- 

 called, in which the usual form of the diphtheria bacillus 

 appears to be wanting. It has occurred to the writer that 

 some atypical variety of the bacillus, of greatly attenu- 

 ated virulence, through a succession of cultures outside 

 the body, may be responsible for this form of throat 

 trouble, often spoken of at such times as sympathetic 

 sore throat. I would regard this form of the disease, in 

 connection with an outbreak of diphtheria, as clear evi- 

 dence that it was becoming endemic in the locality ; in 

 other words, that cultures outside the body were in pro- 

 gress somewhere in the vicinity. 



Mixed infection, or the association of diphtheria bacilli 



