372 



PATHOGENIC BACTERIA. 



nary aqueous solution of the anilin dyes, and also very 

 readily by Gram's method. 



The tetanus bacillus is a common saprophytic organ- 

 ism which can be found in most garden-earth, in dust, 

 in manure, and sometimes in the intestinal discharges 

 of animals. It is extremely difficult to isolate and 

 cultivate, because it will not grow where the smallest 



Fig. 80. — Bacillus tetani : six-days- Fig. 81. — Bacillus tetani : culture 

 old puncture-culture in glucose-gelatin four days old in glucose-gelatin (Fran- 

 (Frankel and Pfeiffer). kel and Pfeiffer). 



amount of oxygen is present It is a typical obligatory 

 anaerobic micro-organism. Curiously enough, in spite 

 of the difficulty that attends the cultivation of the 

 tetanus bacillus, Farran 1 and Grixoni believe it to be 



1 Centralbl.f. Bakt. u. Parisitenk., July 15, 1898, p. 28. 



