626 



PATHOGENIC MICROORGANISMS 



calcification of the necrotic masses, leading to spontaneous cure. As a 

 rule, this process is extremely chronic. Infection in the lungs or in the 

 intra-abdominal organs is, of course, far more serious. When death 

 occurs acutely, it is often due to secondary infection. The disease is 

 acquired probably by the agency of hay, straw, and grain. Berestnew ' 

 has succeeded in isolating actinomyces from straw and hay which he 

 covered with sterile water in a potato jar and placed in the incubator. 

 After a few days small white specks looking like chalk powder appeared 

 upon the stalks, which, upon further cultivation, he was able to identify 

 as the organism in question. 



Animal inoculation, carried out extensively both with pus and with 

 pure cultures by several observers, has yielded little result. Progressive 



Fig. 143. — ^Branching Filaments of Actinomyces. (After Wright and Brown.) 



actinomycotic lesions were never obtained, although occasionally small 

 knobs containing colonies surrounded by epithelioid cells and connective 

 tissue were observed, showing that the invading microorganisms were 

 able to survive and grow for a short time, but were not sufficiently 

 virulent to give rise to an extensive disease process. Transmission from 

 animal to animal, or from animal to man directly, has not been satis- 

 factorily proven. 



Whether or not there are various forms of actinomyces must 

 as yet be regarded as an open question. The investigations of 

 Wolff and Israel, however, together with those of Wright, who alone 

 observed thirteen different strains, seem to indicate that most, if 

 not all, of the cases clinically observed are due to one and the same 

 microorganism. 



1 Berestnew, Ref. Cent. f. Bakt., 24, 1898. 



