THE GROUP OP BAY BACTEEIA 369 



Morphology. — "When the purulent material from a case 

 of lumpy jaw in cattle is examined there will be found 

 many minute yellowish granules sometimes large enough 

 to be observed by the unaided eye. Microscopic examina- 

 tion of these tiny grains show them to be made up of com- 

 pact masses of the organisms arranged more or less radially. 

 When the edge of the granule is examined carefully it will 

 be found to be made up of club-shaped enlargements. The 

 filaments in the middle of the granule are usually half a 

 micron in diameter. 



The organism stains readily with the common aniline 

 dyes and is Gram-positive. When growing upon artificial 

 media it consists of interlacing branched threads, forming 

 a relatively compact mass. 



Culture. — In broth the organism forms distinct spherical 

 mulberrylike masses, generally near the bottom of the tube. 

 Agar cultures, particularly those containing glycerin, show 

 the development of colonies, which resemble tiny drops of 

 amber, which may enlarge and may remain discrete or 

 colorless, or form a distinctly wrinkled membrane, some- 

 times rather dusty in appearance. 



Pathogenesis. — The organism does not appear to be 

 pathogenic for most of the laboratory animals. In most 

 cases the lumpy jaw or wooden tongue of cattle is primarily 

 due to the presence of a splinter or grass awn which has 

 worked its way into the tongue or the gums around the 

 roots of the teeth. These evidently carry with them the 

 spores of the Actinomyces which is then aided in invading 

 the tissues. The swelling or tumorlike mass develops at the 

 side of the infection. This may soften and ultimately dis- 

 charge a yellowish pus. When the tongue is the primary 

 seat of infection, it becomes enlarged, indurated or hardened 

 and may protrude from the mouth. 



The disease apparently is quite noncontagious — it is not 

 at all readily transmitted from one animal to another. 



