294 



ACTINOMYCOSIS AND ALLIED DISEASES. 



exposed to infection from this source. The position of the 

 lesions in cattle is also in favour of such a view. 



Cultivation (for methods of 

 isolation see later). — The actino- 

 myces grows on a variety of 

 media, though on all its rate 

 of growth is somewhat slow. 

 Growth takes place at the ordi- 

 nary room temperature, but very 

 slowly, the temperature of the 

 body being much more suitable, 

 and it would seem that an ana- 

 erobic condition is more produc- 

 tive of positive results in many 

 instances than where oxygen is 

 not excluded. 



On agar or glycerin agar at 

 37° C, growth is generally visi- 

 ble on the third or fourth day in 

 the form of little transparent 

 Fig. 104.— Cultures of the actiiiomyces on drops which gradually enlarge 



glycerm agar, of about three weeks' growth, ^^^ ^^^^ rOUndcd projections of 

 snowing the appearances which occur. _ ^ ■* 



The growth in A is at places somewhat a reddish-ycllow tint and some- 

 corrugated on the surface. Natural size, ^j^^^ transparent appearance, 



like drops of amber. The growths tend to remain separate, and 

 even when they become con- 

 fluent, the nodular character 

 is maintained. They have a 

 tough consistence, being with 

 difficulty broken up, and ad- 

 here firmly to the surface of 

 the agar. Older growths often 

 show on the surface a sort of 

 corrugated aspect, and may 

 sometimes present the appear- 

 ance of having been dusted 

 with a brownish-yellow powder 

 (Fig. 104). The organism 

 grows well in the anaerobic 

 condition on agar, and for this 



Fig. 105. — Actinomyces from a culture 

 on glycerin agar, showing the branching of the 

 filaments. Stained with fuchsin. X 1000. 



