296 Manual of Veterinary Microbiology. 



times digestive mucous membrane. This disease 

 has been thoroughly studied in man ; it also occurs 

 in certain species of animals, particularly in birds and 

 in the calf. At one time it was believed that human 

 and avian diphtheria were identical, but this view is 

 no longer entertained. The two diseases have a 

 different evolution and different microbes. 



Human diphtheria. — Klebs and Loffler discovered in 

 the false membranes a bacillus, straight or curved, 

 with rounded ends, sometimes club-shaped, at other 

 times less than the average thickness. It meas- 

 ures 2'5/z to 3/i in length by 0-7;/ in thickness; it is 

 especially aerobic but also grows when the air is ex- 

 cluded; it is met with in the superficial zone of the 

 false membranes. The germ grows on most of our 

 artificial media; it is stained by Loffler's methylene 

 blue and by the Gram method. Roux and Yersin 

 have completed its biological study ; they isolated it 

 by inoculating a series of serum tubes without re- 

 charging the platinum w^ire : the colonies of diph- 

 theritic bacilli appear as grayish-white rounded 

 growths with the center more opaque than the 

 periphery. 



Excoriated mucous membranes, inoculated with a 

 culture, soon show the characteristic false membrane 

 in rabbits, guinea pigs, cats, pigeons, and chickens. 



The subcutaneous injection of a few drops of the 

 liquid kills the guinea pig in thirty-six hours with 

 general vascular dilatation and pleural effusion. The 

 rabbit requires 1 cc. of the culture and, like the pigeon, 

 dies after several days. The dog and the sheep also 

 succumb. In all cases a hemorrhagic cedema is pro- 

 duced at the place of inoculation and the vessels of 



