PATHOGENIC BACTERIA. 283 



As is well known, the pseudomembranous affection pro- 

 duced by the diphtheria bacillus in man is generally seen in 

 the larynx and pharynx. Membranous rhinitis is also caused 

 by the diphtheria bacillus. On the other hand, pseudomem- 

 branous affections of the larynx and pharynx may be produced 

 by streptococci.* Pseudomembranes occurring in the throat 

 during scarlet fever and measles may be due to the diphtheria 

 bacillus, but are more often caused by streptococci. The 

 affection known as membranous croup is usually diphtheria of 

 the larynx, produced by the diphtheria bacillus. The diph- 

 theria bacillus is a rare cause of puerperal fever. Although 

 the uninjured skin is not attacked by the diphtheria bacillus, 

 it may be present in pseudomembranes on wounded surfaces, 

 usually in connection with diphtheria in the throat. Most 

 'pseudomembranes formed upon wounds of the skin are pro- 

 duced by other bacteria than the diphtheria bacillus, as is also 

 the case with the pseudomembranous inflammations of the 

 intestines and bladder. Although such inflammations are often 

 called "diphtheritic," it must be remembered that the ex- 

 pression is used in an anatomical sense, meaning that a fibrin- 

 ous pseudomembrane has formed, extending deeply into the tis- 

 sues, which is not necessarily caused by the diphtheria bacillus. 



In cases of diphtheria in man,f the diphtheria bacillus is 

 generally found limited to the vicinity of the pseudomem- 

 brane, and at autopsies it is not usually found in the internal 

 viscera, excepting in the lungs, where diphtheria bacilli may 

 or may not be present when diphtheria is complicated with 

 bronchopneumonia. The general symptoms of the disease, 

 including the paralysis which sometimes follows it, are due 

 to the toxins produced by the bacilli in the throat. 



* Bissell. Medical News. May 31, 1902. American Journal Medical 

 Sciences. February, 1903. Review of Work of Massachusetts Boards of 

 Health. 



f For a full study of the lesions of diphtheria see the Monograph of Council- 

 man, Mallory and Pearce. Boston. 1901. 



