462 APPLICATION OF METHODS OF BACTERIOLOGY 



The young colonies appear as grayish points composed of 

 a felt-work of fine threads. As the colonies become older 

 they become denser and more opaque. Very old colonies 

 are almost leathery in consistency. On blood serum the 

 growth after a time assumes a salmon, an orange, or a 

 yellowish-red color. Growth on gelatin is accompanied by 

 slow liquefaction. 



A yellowish-red growth, limited in extent, occurs on 

 potato. It causes no clouding of bouillon, but grows as 

 cottony clumps that sink to the bottom. 



The bulbous extremities seen upon the mycelial threads 

 fresh from the pus are not usually seen under conditions 

 of artificial cultivation. They are sometimes observed in 

 colonies located in the depths of solid media. The white, 

 powdery coating seen on old colonies represents the so-called 

 "spores." They are not, however, resistant to heat, being 

 destroyed, according to Domec, by 75 C. in five minutes. 



Bo vines are the animals most frequently affected. The 

 disease has been seen in swine, dogs, and horses. 



The most common seat of the disease is the jaw, and this, 

 together with the fact that particles of fodder, such as bits 

 of grain, chaff, straw, and barley beard, have been detected 

 in the diseased tissues in association with the causative 

 fungus, has led to the belief that the parasite gains access 

 to the tissues with such foodstuffs. It has not, however, 

 been recognized outside the animal body. The disease is 

 apparently not transmissible from animal to animal or from 

 animal to man. Inoculation of animals with pure cultures 

 is usually negative, although nodular formations have fol- 

 lowed the injection of large quantities into the peritoneal 

 cavity of rabbits. In Bostrom's cases the nodules presented 

 only a few of the club-shaped extremities of the ^threads, 



