ANTHRAX 65 



the end of a straight platinum needle into the fluid, and then 

 driving it into the gelatin. 



The other culture is made by blowing a drop or two of the 

 fluid into a tube of gelatin melted at the body temperature. 



FIG. 16. PETRI'S DISH. 



The two are to be thoroughly mixed together and then poured 

 into a Petri dish (Fig. 16), previously sterilized by dry heat 

 and allowed to cool. 



Both cultures are incubated at a temperature of about 20 C. 

 In about two days the gelatin stab-tube will show a very 

 characteristic appearance if the anthrax 

 bacilli are present in pure culture. The 

 growth takes place in lines which project 

 nearly at right angles to the line of inocu- 



p IG . !8. YOUNG COLONY OF ANTHRAX BACILLUS 

 ( x 15). (CROOKSHANK.) 



lation, and grow more vigorously the nearer 

 they are to the surface. The result is the 

 BACILLUS. (CROOK- development of a culture which has a 

 strong resemblance to an inverted fir-tree 

 (Fig. 17). In another day or two the 

 gelatin will begin to show a certain amount of liquefaction, 

 which begins at the surface. 



5 



