386 BACTERIOLOGY. 



thicker than the cell (from I ft to 1.5// in diameter), 

 occupying one of its extremities and giving to the rods 

 the appearance of small pins (Fig. 48). It is stained 

 with the ordinary aniline dyes, and is not decolorized 

 by Gram's method. The spores may be demonstrated 

 by double-staining with ZiehPs method. 



FIG. 48. 



Tetanus bacilli with spores in distended ends. X 1100 diameters. 



Biology. An anaerobic, liquefying, motile (though not 

 very actively motile) bacillus. Forms spores, and in 

 the spore stage it is not motile. It does not grow at 

 temperatures below 14 C., but grows slowly at tem- 

 peratures from 20 to 24 C., and best at 37 C., when 

 it rapidly forms spores. It will not grow in the pres- 

 ence of oxygen or carbon dioxide gas, but grows well in 

 an atmosphere of pure hydrogen. 



The bacillus of tetanus grows in ordinary nutrient 

 gelatin and agar of a slightly alkaline reaction. The 

 addition to the media of 1.5 per cent, of glucose causes 

 the development to be more rapid and abundant. It 

 also grows abundantly in alkaline bouillon under an 

 atmosphere of hydrogen. 



