586 DISEASE IN WILD MAMMALS AND BIRDS 
long enough for the preparation of a vaccine, which will 
be described later, when by mischance it was lost. In 
1920 another successful cultivation occurred, this time by 
incising a mass in the soft subungual tissue and plating 
in the same manner; upon this culture the biology is 
described. Smear preparations offer no more than has 
already been mentioned. 
Colonies develop upon blood serum plates as opaque, 
pale yellow, circular, discrete masses with a slightly 
depressed uneven centre, but without umbilication. 
They remain smooth and slightly glistening for several 
days, then become sUghtly wrinkled and twisted with a 
more definitely raised edge and a tendency to an uneven 
sinking in of the centre. Transfers to agar slants show 
wrinkled continous opaque, dull yellow, sharply outlined 
growths which soon wrinkle, fold, and twist like certain 
tubercle bacillus cultures. Spreading occurs, but is slow 
after forty-eight hours. As medium becomes drier it is 
possible to see a thin, colorless, wrinkled film stretching 
out from the main gro\\i;h. If the medium be dry or old 
or if only a small portion of seed material be used and 
this scattered over the surface of the slant, discrete 
colonies arise. These are circular, seldom exceeding 
3 mm., dirty yellow-white, distinctly umbilicated and 
without clear film of spreading around them. 
In nearly all quite old cultures, a white chalky efflorescence appears 
over the surface. 
The morphology of the young agar culture is chiefly mycelial or 
filamentous, whereas from a culture on dried media and those show- 
ing efflorescence, the organisms are short, heavy, deeply granular and 
of the mycobacterial type. 
Glycerine agar. — Corresponds to agar. 
Blood agar. — Similar to agar but much less luxuriant. 
Blood serum. — Limited dirty yellow, raised, dull, wrinkled and 
granular, tightly adherent to the medium. 
Potato. — Spreading, dirty yellow, much wrinkled, friable, tightly 
adherent. 
Gelatine. — Limited growth as a wrinkled, tough scum only 
on surface. 
