PATHOGENIC BACTERIA. 299 



tive form. This is the shape which the organism presents as 

 it grows in the animal body. The club-shaped ends are gen- 

 erally regarded as a degenerative or involution form. Trans- 

 verse divisions may sometimes be distinguished upon the 

 threads. Spherical forms resembhng micrococci may appear 

 which may possibly be spores. In some members of this group 

 spores — conidia — form in cultures on the ends of the filaments. 

 The organism stains with the ordinary aniHne dyes, by Gram's 

 method or the Weigert fibrin stain. 



The fungus may be cultivated upon the usual culture- 

 media, though not easily. It is facultative anaerobic. It 

 grows both at ordinary temperatures and in the incubator. 

 The growth is not rapid. The colonies are fine, dry, elevated, 

 irregular in form, becoming opaque. Bulbous ends upon the 

 threads do not usually appear in cultures. The results of the 

 injection of these cultures into the lower animals are as yet 

 uncertain. 



The disease produced by the ray-fungus is called actino- 

 mycosis. It occurs in cattle chiefly, seldom in swine and 

 horses, and occasionally in man. Infection appears to be 

 carried by grain or particles of vegetable fiber which pene- 

 trate the tissue. The presence of such foreign particles as 

 well as the organisms appears to favor infection. The infec- 

 tious material frequently enters through the mouth, espe- 

 cially in the vicinity of the teeth, but it may also occur through 

 the skin or the mucous membranes. It leads to the formation 

 of inflammatory, tumor-Uke nodules, hence the name "lump- 

 jaw " given to the disease in cattle. Necrosis of the tissue takes 

 place with the formation of an abscess. The pus is pecuhar 

 in containing small yellowish-white particles — so-called "sulphur 

 granules " — which consist of Httle clumps of the ray-fungus, and 

 which readily permit the disease to be diagnosed by the micro- 

 scope. The material may be examined in the perfectly fresh 

 condition without any staining. The jaw or its neighborhood 



