386 BACTERIOLOGY. 
thicker than the cell (from 1p to 1.5» in diameter), 
occupying one of its extremities and giving to the rods 
the appearance of small pins (Fig. 48). Itis stained. . 
with the ordinary aniline dyes, and is not decolorized 
by Gram’s method. The spores may be demonstrated.” 
by double-staining with Ziehl’s method. 
Fig. 48. 
rs a 
Tetanus bacilli with spores in distended ends. X 1100 diameters. 
Biology. An anaérobic, 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. 
