374 BACTERIOLOGY. 
tions of the throat belonging to both diphtheritic and 
to non-diphtheritic inflammations which appear exactly 
alike, having apparently similar symptoms and similar 
duration; that it is even possible to examine two cases, 
knowing that one is surely diphtheria, or at least that 
diphtheria bacilli are present in the exudate, and the 
other surely is not, and yet be unable to determine 
clinically which is true diphtheria and which’ is pseudo- 
diphtheria. It is not meant to imply that a case is 
one of true diphtheria simply because the diphtheria 
bacilli are present, but rather that the doubtful cases 
not only have the diphtheria bacilli in the exudate, 
but are capable of giving true characteristic diphtheria 
to others, or later develop it characteristically them- 
selves; and that those in whose throats no diphtheria 
bacilli exist can under no condition give true character- 
istic diphtheria to others or develop it themselves unless 
they receive a new infection. It is, indeed, true, as a 
rule, that cases presenting the appearance of ordinary 
follicular tonsillitis in adults are not due to the diph- 
theria bacillus. It is also true that now and then a case 
having this appearance is one of diphtheria, and almost 
every physician has. seen such cases from time to time 
in households infected with diphtheria. On the other 
hand, in small children mild diphtheria very frequently 
occurs with the semblance of rather severe ordinary 
follicular tonsillitis, due to the pyogenic cocci, and in 
large cities where diphtheria is prevalent all such cases 
must be watched as being more or less suspicious. 
As showing our doubt in our own judgment, I think 
most would feel that if in any case exposure to diph- 
theria is known to have occurred, even a slightly sus- 
picious sore-throat would be regarded as probably due to 
