632 INFECTION AND IMMUNITY. 



tongue), or in carious teeth. Transmission to man 

 by eating the meat of actinomycotic cattle has not 

 been noted. In man the disease is primary in the 

 internal organs (lungs, intestines, liver, brain, 

 etc.) in a large percentage of the cases, whereas 

 "lumpy jaw" is rare. The disease extends locally 

 Ly the gradual involvement of adjacent tissues, 

 which in time become occupied by sinuses, ab- 

 scesses and masses of connective tissue. Numerous 

 "spores" and bacillus-like cells, having their source 

 in the fungous threads, abound in the vicinity of a 

 colony. The occurrence of such forms in leuco- 

 cytes and other large mononuclear cells has led 

 some to the view that the micro-organisms may 

 be carried to neighboring tissues or to distant 

 parts as cell inclusions. In cattle the disease usu- 

 ally is more chronic than in man, more fibrous tis- 

 sue is formed and metastases in internal organs 

 are less frequent. In man the lesions are more 

 purulent in character, large abscesses sometimes 

 form as in the liver, and metastases in visceral or- 

 gans are more common. Cases of general acti- 

 nomycosis are occasionally met with in both cattle 

 and man. 



Prophylaxis. Little can be said in the way of prophylaxis 

 against actinomycosis. Knowing the part that in- 

 fected grains, straws, etc., play in causing infec- 

 tion,, the practice of biting or chewing grains or 

 of using straws as toothpicks, evidently is one 

 which affords opportunity for infection. The pres- 

 ence of carious teeth has often been suggested as 

 a predisposing condition for infection. 

 immunity Practically nothing is known concerning the de- 



aml fnfmty. gree to which susceptibility to actinomycosis pre- 

 vails, and the question of immunity to the disease 



