ANTHRAX. 9 
present in pure culture. The growth takes place in 
lines which project nearly at right angles to the line of 
inoculation, and grow more vigorously the nearer they 
are to the surface. The result is the development of 
a culture which has a strong resemblance to an inverted 
fir-tree (fig. 14). In another day or two the gelatin 
will begin to show a certain amount of liquefaction at 
the surface. 
The appearances in the plate-culture are perhaps not 
quite so characteristic, but they are manifested in 
impure cultures. The young colonies of anthrax bacilli 
Fic. 15.—Young colony of anthrax bacillus (xX 15). (Crookshank). 
have a whorled appearance which has been compared to 
a barrister’s wig or to the head of Medusa (fig. 15). The 
plate should be placed upon the stage of the microscope 
and examined for these colonies with the low power. 
If one is found a clean cover-glass should be pressed 
upon it, lifted up with a needle so as to bring up the 
colony with it, fixed by heat, and stained with carbol- 
thionin or methylene blue. The colonies are most 
characteristic after two days incubation; at a later 
period the gelatin is liquefied and spores are formed. 
