624 



PATHOGENIC MICROORGANISMS 



or whether it contains large numbers of other bacteria. In the latter 

 case it may be almost impossible to obtain cultures. The descriptions 

 of methods of isolation and of cultural characteristics given by various 

 writers have shown considerable differences. The most extensive 

 cultural work has been done by Bostroem/ Wolff and Israel, and by J. 

 H. Wright. Bostroem has described his cultures as aerobic, but Wolff 

 and Israel ' and Wright ^ agree in finding that the microorganisms iso- 



Fig. 141. — ^Actinomyces Granule Crushed Beneath a Cover-glass. Un- 

 stained. Low power. Shows radial striations. (After Wright and Brown.) 



lated by them from actinomycotic lesions grow but sparsely under aerobic 

 conditions and favor an environment which is entirely free from oxygen, 

 or at least contains it only in small quantities. The method for isolation 

 recommended by Wright is, briefly, as follows: Pus is obtained, if 

 possible, from a closed lesion and washed in sterile water or broth. The 

 granules are then crushed between two sterile slides and examined for 



1 Bostroem, Beitr. z. path. Anat. u. z. allg. Path., ix, 1890. 



2 Wolff -and Israel, Virch. Arch., 126, 1891. 



3 J. H, Wright, Jour. Med. Res., viii, 1905. 



