DIPHTHERIA. 53 



noting each characteristic and comparing it with those 

 described above. 



The beginner is strongly recommended to procure a 

 series of slides of diphtheria bacilli from a bacterio- 

 logical laboratory and to study them carefully. 



Hoffman's bacillus (Plate I., fig. 2) is a modified 

 form of the true diphtheria bacillus, and is frequently 

 met with in throat cultures. It is about as long as 

 the short form of diphtheria bacillus, but decidedly 

 plumper and is more uniform in shape and size. 

 These bacilli stain uniformly and deeply. They ex- 

 hibit the same arrangement, and are often grouped in 

 pairs. Clubbed forms do not occur. 



The diphtheria bacilli which occur in films made 

 direct from the swab are similar to those seen in 

 cultures, but are often thicker ; they may stain uni- 

 formly, and clubbed forms are rare. It is unusual to be 

 able to make an absolute diagnosis as to their nature, 

 but it may be done at times. Yet such an examination 

 is often useful. If suspicious bacilli are present you 

 should inject antitoxin forthwith ; if no suspicious 

 bacilli are seen it is safe to wait for the result of the 

 cultural examination. 



INTERPRETATION OF RESULTS. 



The discovery of the diphtheria bacillus in the exudate may 

 mean : 



(a). That the patient is suffering from diphtheria. 



(b). That he has suffered from diphtheria and is now 

 convalescent but is still infectious. The bacilli may 

 persist for weeks or months and while they do so the 



