374 



TETANUS 



contents of dung -heaps, where it probably leads a saprophytic 

 existence, though its function as a saprophyte is unknown. 

 From such sources and from the pus of wounds in tetanus, 

 occurring naturally or experimentally produced, it has been 

 isolated by means of the methods appropriate for anaerobic 

 bacteria. The best methods for dealing with such pus are as 

 follows : 



(1) The principle is to take advantage of the resistance of 



FIG. 125. Tetanus bacilli, showing flagella. 

 Stained by Rd. Muir's method. x 1000. 



the spores of the bacillus to heat. A sloped tube of inspissated 

 serum or a deep tube of glucose agar is inoculated with the 

 pus and incubated at 37 C. for forty-eight hours, at the end of 

 which time numerous spore-bearing bacilli can often be observed 

 microscopically. The culture is then kept at 80 C. for from 

 three-quarters to one hour, with the view of killing all organisms 

 except those which have spored. A loopful is then added to 

 glucose gelatin, and roll-tube cultures are made in the usual 

 way and kept in an atmosphere of hydrogen at 22 C. ; after 

 five days the plates are ready for examination. Kitasato com- 



