BACTERIA PATHOGENIC FOR ANIMALS, NOT FOR MAN 199 



Origin. In 1879 Perroncito observed this cocci-like ba- 

 cillus in diseases of chickens, and Pasteur, in 1880, isolated 

 and reproduced the disease with the bacillus in question. 



Form. At first it was thought to be a micro- 

 coccus, but it has been found to be a short rod, 

 about twice as long as it is broad, the ends 

 slightly rounded. The center is very slightly 

 influenced by the anilin colors, the poles 

 easily, so that in stained specimens the bacil- 

 lus looks like a dumb-bell or a figure-of-eight chickl'n 

 (Microbe en huit) . in blood (x 1000) 



T-, , . mi i i f (Frankel and 



Properties. They do not possess self-move- pfeiffer). 



ment; do not liquefy gelatin. 



Growth. Occurs at ordinary temperature, requiring oxygen 

 for development. It grows very slowly. 



Gelatin Plates. In the course of three days little round, 

 white colonies, which seldom increase in size, having a rough 

 border and very finely granulated. 



Stab-cultures. A very delicate gray line along the needle- 

 track, which does not become much larger. 



A gar Stroke Culture. A moist, grayish-colored skin, more 

 appreciable at brood-heat. 



Potato. At brood-heat, after several days, a very thin, trans- 

 parent growth. 



Staining. Methylene-blue gives the best picture. Gram's 

 method is not applicable. As the bacillus is easily decolorized, 

 anilin-oil is used for dehydrating tissue sections, instead of 

 alcohol. 



Method: 



Loffler's methylene-blue J hour 



Alcohol 5 seconds 



Anilin-oil 5 minutes 



Turpentine i minute 



Xylol and Canada balsam. 



Pathogenesis. Feeding the fowls with the bacilli or inject- 

 ing them under the skin will cause death in from twelve to 



