Cultivation 



397 



others, and the great majority of the spores, were destroyed. 

 As scarcely anything but the tetanus spores remained alive, 

 their subsequent growth gave a fairly pure culture. 



Cultivation. The tetanus bacillus is difficult to culti- 

 vate, because it will not grow where the smallest amount 

 of free oxygen is present. It is hence a typical obligatory 



Fig. 117. Bacillus tetani; six- Fig. 118. Bacillus tetani; cul- 



days-old puncture culture in glu- ture four days old in glucose- 

 cose-gelatin(Frankel and Pfeiffer). gelatin (Frankel and Pfeiffer). 



anaerobe. Farran * and Grixoni believe it to have originally 

 been an optional anaerobe, and it is said by these writers 

 that the organism can gradually be accustomed to oxygen 

 so as to grow in its presence. When this is achieved, it 

 loses its virulence. 



* "Centralbl. f. Bakt. u. Parasitenk.," July 15, 1898, p. 28. 



