516 



BACTERIOLOOY. 



Fig. 97. 



It grows in ordinary nutrient gelatin and agar-agar 

 of a slightly alkaline reaction. Gelatin is slowly lique- 

 fied, vfiih. the coincident production of a small amount 

 of gas. Neither agar-agar nor 

 blood-serum is liquefied by its 

 growth. 



The addition to the media of 

 from 1.5 to 2 per cent, of glucose, 

 0.1 per cent, of indigo-sodium 

 sulphate, or 5 per cent, by volume 

 of blue litmus tincture favors its 

 growth. 



It grows well in alkaline bouil- 

 lon under an atmosphere of hy- 

 drogen. 



Under artificial conditions it 

 may be cultivated through nu- 

 merous generations without loss 

 of virulence. 



Appearance of the Colo- 

 nies. — Colonies of bacillus tetani 

 on gelatin under an atmosphere 

 of hydrogen have, in their early 

 stages somewhat the appearance 

 of the colonies of the common 

 bacillus subtilis in their earliest 

 stages, viz., they have a dense, 

 felt-like centre surrounded by a 

 fringe of delicate radii. The 

 liquefaction is so slow that the 

 appearance is retained for a rela- 

 tively long time, but eventually 

 becomes altered. In very old 



Colonies of the tetanus 

 bacillus four days old,iiiade 

 by distributing the organ- 

 isms through a tube nearly 

 filled with glucose-gel- 

 atin. Cultivation in an at- 

 mosphere of hydrogen, 

 (From Frankel and 

 Pfeiffek.) 



