358 CLINICAL BACTERIOLOGY. 



perature of 37 C. (98.6 F. ) numerous small, isolated nodules 

 resembling dewdrops, the first indications of which are visible 

 with a lens as early as after two days, but which do not appear 

 distinctly before from the third to the fifth day. These project 

 above the surface as spheres, though at times they are not 

 entirely round. They grow quite slowly, often only reaching 

 the size of a pinhead after eight days, and they usually do not 

 grow larger. At the same time they become opaque. As a rule, 

 they do not become confluent, remaining isolated for weeks 

 and months. If, after inoculation, a veil-like turbidity appears 

 on the surface of the agar, the nodules described often become 

 differentiated subsequently. At times, however, the nodules 

 coalesce into a whitish coating. The actinomyces-granules 

 used for inoculation undergo enlargement as a whole, if not 

 carefully rubbed upon the inoculated surface, and form a whitish 

 area in which, however, at times, also a differentiation into 

 nodules is discernible. In addition to these fine nodules there 

 are present in small number white nodules, rather larger than 

 lentils, with a blunt, club-shaped, projecting center, and which 

 become covered over toward the periphery, and frequently ex- 

 hibit roundish depressions at quite regular intervals. These 

 nodules in roset-form, whose periphery, further, is not always 

 regular, but at times is only slightly excavated or cleft, are also 

 characterized by their growth into the body of the culture- 

 medium ; they send root-like processes into the agar. These" 

 large nodules are not common, and are usually encountered 

 only in small number in culture. As, in addition to them, the 

 smallest nodules first described are often present also, and as, 

 further, nodules of intermediate size transition-forms with 

 root-like processes appear, Wolff and Israel consider the char- 

 acteristic large nodules only as the highest macroscopic form of 

 development of the inoculated actinomyces-fungus. 



In stab -cultures, in addition to enlargement of the intro- 

 duced granules, there develops throughout the entire length of 

 the puncture a delicate, gray, veil-like turbidity, and this likewise 

 contains numerous small nodules. At times large, flat, white 

 plaques form at the site of puncture. 



The cultures described develop typically only in the absence 

 of oxygen ; otherwise the growth is but scanty. A tempera- 

 ture of 37 C. (98.6 F.) is always necessary for the cultivation 

 of the fungus, and no development takes place at temperatures 

 between 16 C. (60.8 F.) and 20 C. (68 F.). For this 

 reason growth does not take place upon gelatin. 



In bouillon growth is quite scanty. After from three to five 

 days white scales and dots appear ; the bouillon itself, like the 

 water of condensation in agar-cultures, remains clear. 



Culture in Eggs. The actinomyces thrives well in pigeons* 



