428 



PRINCIPLES OF VETERINARY SURGERY 



but may sometimes be found in the middle of the bacillus, 

 or even at the two extremities. It is always thicker than 

 the rod and may reach a width of 1.5 microns. In very old 

 cultures they are only spores, — the rod has disappeared. 



STAINING. — The bacillus of Nicolaier is easily stained 

 with any of the aniline colors, gentian violet, etc., and by 

 Ziehl's or Gram's method. The spores are well stained by 



Fig. 41. 

 Bacillus of Nicolaier. Twelfth day. 



Ziehl's or Ehrlich's stain, and the flagella by Van Ermeng- 

 lien's process. 



CULTURES.— The bacillus of tetanus is anaerobic. It 

 may be cultivated in slightly aerated environments, but 

 beautiful colonies are obtained only in a vacuum or in hy- 

 drogen. Any of the media may be used. The tempera- 

 ture which favors its growth varies between 14 and 43 de- 

 grees. The most favorable temperature is 38 to 39 degrees. 



The aspect of the cultures varies with the media. In 

 the alkaline bouillons, containing 2 per cent of glucose, and 



