DIPHTHERIA 



I0 3 



other sources. It is interesting to note that 32% of these people showed pseudo- 

 diphtheria bacilli. 



Infection of the larynx and middle ear are not very rare. The mu- 

 cous membrane of the vagina or the conjunctiva may also be infected. 

 The B. diphtheria may be in pure culture lying entangled in the fibrin 

 meshes or contained within leukocytes in the membrane or be asso- 

 ciated with staphylococci, pneumococci, or especially streptococci. 

 These latter complicate unfavorably and cause the suppurative con- 

 ditions about the neck. In fatal cases the diphtheria bacillus may be 

 found in the lungs. Ordinarily, however, it remains entirely local and 

 does not get into the circulation or viscera. 



FIG. 28. Diphtheria bacilli involution forms. (Kolle and Wassermann.) 



It produces soluble absorbable poisons which are designated toxin in the case 

 of the one responsible for the acute intoxication, parenchymatous degeneration and 

 death and toxone for the poison which produces oedema at the site of inoculation and 

 postdiphtheritic palsy. The injection of the soluble poisons alone without the bacilli 

 produces the symptoms of the disease. 



The bacilli tend to appear as slightly curved rods, showing varying 

 irregularities in staining, as banding or beading, and in particular the 

 presence at either end of small, deeply staining dots (metachromatic 

 granules). 



These granules may be seen in an eighteen-hour culture, but are more abundant 

 after thirty-six hours. The granules are well seen with Loffler's blue, but better 

 with Neisser's method. In culture the bacilli show swelling at one or both ends or 

 clubbing. In secretions or in culture they show V-shapes or false branching and, 

 what is most characteristic, the parallelism four or five bacilli lying side by side like 



