268 BACTERIOLOGY FOR NURSES 



cally so closely resembled tuberculosis that no means of distin- 

 guishing the two forms of disease could be devised save that of 

 finding the causative organism. 



Subcutaneous injections into rabbits cause the formation of 

 abscesses, which when incised are found to contain a thick muci- 

 laginous fluid; intravenous injections produce a rapidly fatal 

 infection. 



In smears made from cultures the organisms have a fine slender 

 appearance, the branching is unsymmetrical and almost at 

 right angles to the stem. When properly stained a distinct bead- 

 ing of the protoplasm may be observed; stained by Gram's 

 method they retain the violet color. In broth cultures growth 

 appears as minute white fluffy tufts clinging to the sides of the 

 tube when left undisturbed. Small colonies appear on Loeffler's 

 serum after three to five days' incubation at 37 C. 



Actinomyces. Actinomycosis has been the most studied of 

 the group of diseases caused by the higher bacteria. It occurs 



chiefly in cattle, but occasionally in 

 other animals and in man. The dis- 

 ease was described early in the nine- 

 teenth century under the name of 

 osteosarcoma. Later in 1877 Bollinger 

 discovered the specific parasite, and 

 the botanist Harz, who studied the 

 organism, gave to it the name Actino- 

 myces or ray fungus, on account of 



FIG. 39. Actinomyces. 'he y-like formation of its growth 

 in the tissues. 



Actinomycosis is an inflammatory condition characterized 

 by the presence of " granules," which are small round masses or 

 colonies of the parasite. To the naked eye the largest appear 

 as yellow or greenish points about the size of a small pin's head. 

 When suppuration has occurred they appear free in the pus, other- 

 wise they may be found embedded in the granulation tissue. 

 According to their age and their structure they may appear as a 

 whitish yellow, a green black, or more rarely red. Microscopically 



