318 BACTERIA 



ularly and sometimes dichotomously. The extremities of the 

 branches develop the club-shaped bodies. The clubs are closely 

 packed together, so that a more or less globular body is formed, 

 with a central core composed of a dense mass of threads " 

 (Crookshank). 



Possibly these clubs represent organs of fructification, and 

 produce the spores. These latter are, it is believed, set free 

 in the vicinity of the ray, and create fresh centres of disease. 



In man the disease manifests itself in various parts ac- 

 cording to the locality of entrance. When occurring in the 

 mouth it attacks the lower jaw most frequently. In one 

 recorded case the disease was localised to the bronchi, and 

 did not even extend into the lungs. It was probably con- 

 tracted by inhalation of the parasite. The disease may 

 spread to distant parts by means of the blood stream, 

 and frequently the abscesses are apt to burrow in various 

 directions. 



In the ox the disease remains much more localised, and 

 frequently occurs in the lower jaw, palate, or tongue. In 

 the last site it is known as " wooden tongue," owing to 

 the hardness resulting. The skin and subcutaneous tissues 

 are also a favourite seat of the disease, producing the so- 

 called wens or clyers so commonly seen in the fen country 

 (Crookshank). Actinomycosis in cattle is specially preval- 

 ent in river valleys, marshes, and on land reclaimed from 

 the sea. The disease occurs at all seasons, but perhaps 

 more commonly in autumn and winter. It is more fre- 

 quently met with in young animals. The disease is prob- 

 ably not hereditary nor readily communicated from animal 

 to animal. 



Actinomyces may be cultivated, like other parasitic dis- 

 eases, outside the body. Gelatine, blood serum, agar, 

 glycerine agar, and potato have been used for this purpose. 

 After a few days on glycerine agar at the temperature of 

 the blood little white shining colonies appear, which in- 



