356 



TETANUS. 



isolation based on the same principle as the last may be 

 adopted. Inoculations with the suspected material are 

 made in half a dozen deep tubes of glucose agar, previously 

 melted and kept at a temperature of 100 C. After inocula- 

 tion they are again placed in boiling 

 water and kept for varying times, say 

 for half a minute, for one, three, four, 

 five, and six minutes, respectively. They 

 are then plunged in cold water till cool, 

 and thereafter placed in the incubator at 

 37 C., in the hope that in one or other 

 of the tubes all the organisms present will 

 have been killed, except the tetanus spores 

 which can develop in pure culture. 

 Another variation may be adopted by 

 making use of Vignal's method (p. 66) at 

 any stage of the procedure just described. 

 The isolation of the tetanus bacillus is 

 in many cases a difficult matter, and 

 various expedients require to be tried. 



Characters of Cultures. Pure 

 cultures having been obtained, sub- 

 cultures can be made in deep upright glu- 

 cose gelatine or agar tubes. On glucose 

 gelatine in such a tube there commences, 

 an inch or so below the surface, a growth 

 consisting of fine straight threads, rather 

 longer in the lower than in the upper 



8b P arts of the tube > radiating out from the 



culture oftheetanus 

 bacillus in glucose needle track (Fig. 89). Slow liquefac- 

 gelatine, showing the tion of the gelatine takes place, with 

 flight gas formation. In agar the growth 

 is not characteristic, consisting of small 

 nodules along the needle track, with irregular short off-shoots 

 passing out into the medium. There is slight formation 

 of gas and, of course, no liquefaction. Growth also occurs 

 in blood serum and also in glucose bouillon under anaerobic 

 conditions. The latter is the medium usually employed for 



