PATHOGENIC BACTERIA. 345 



seminated throughout the whole body. The death of the 

 animal, therefore, is due to the poisons elaborated by the 

 diphtheria bacilli — either poisons introduced at the original 

 injection, or substances produced by the bacilli which may 

 have multiplied in the animal's body. The internal viscera, 

 especially the liver, often exhibit small areas consisting of 

 necrotic cells; a transudation of serum takes place in the great 

 serous cavities, and the lymph-nodes are swollen. A genuine 

 diphtheritic membrane may be produced on the trachea of a 

 young kitten by rubbing into it a part of a culture of the diph- 

 theria bacillus. 



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 indistinguishable 

 from diphteria except by bacteriological examination may be 

 produced by streptococci.* Pseudomembranes occurring in the 

 throat during scarlet fever and measles may be due to the diph- 

 theria 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 "diphtheric," it must be remembered that the ex- 



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

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

 Health. 



