ANTHRAX. 



195 



or specks, which, on examination with a low power of the microscope 

 and small diaphragm, exhibit two distinct forms. One form, on 

 careful focussing, has the appearance of a little compact ball of 



FIG. 96. MARGIN OP A COLONY, x 250 



twisted threads ; in the other, liquefaction of the gelatine has 

 commenced, and the threads spread out like locks or plaits of 

 hair in the neighbouring gelatine. These appearances are perfectly 

 characteristic (Figs. 94, 96). 



Cover-glass Impressions. The plate- cultivations should be also 

 examined as soon as the colonies 

 appear, by making cover-glass im- 

 pressions (Fig. 95). The filaments, 

 examined with a high power, will be 

 seen to consist of a number of rods 

 or segments which are perfectly 

 regular in form. On the other 

 hand, filaments from a tube-cultiva- 

 tion in a solid medium will often be 

 found to be composed, not only of 

 rods, but here and there of the so- 

 called involution-forms (Fig. 97). FIG. 97. FILAMENTS WITH OVAL AND 



, , . i IRREGULAR ELEMENTS, X 800. 



From cultures m gelatine and 



glycerine agar, very striking preparations are sometimes 'obtained, 



with numerous large spherical and lemon-shaped elements. In a 



