TETANUS 51 



If cultures are to be taken, add a pipette (see Fig. 10, b\ a 

 deep tube of agar to which 2 per cent, of grape-sugar has been 

 added previous to sterilization, a flask of water, and a ther- 

 mometer. 



Method. Scrape the deeper portions of the wound with 

 the platinum loop, and spread out the secretion thus obtained 

 on the surface of a slide. Prepare several of these slides, and 

 fix the film by heat. Stain some by the simple stain for two 

 minutes and others by Gram's method. 



The bacillus of tetanus is about as long as the tubercle 

 bacillus, and is very slender. It stains by Gram's method. A 

 very characteristic feature is its method of spore-formation. 

 The spores are spherical bodies which are formed at the 

 extremities of the bacilli, giving them the appearance of pins 

 or drumsticks. The spores do not stain by the ordinary stains, 

 and appear as colourless and highly refractile bodies (Plate 

 II, Fig. i). 



The cultures are made in agar to which 2 per cent, of grape- 

 sugar is added, and the needle or pipette used in making the 

 inoculation is plunged deep down into the medium. The 

 bacillus of tetanus is an anaerobe i.e., it grows only in the 

 absence of oxygen. The stabs are made deep in order to 

 inoculate the material far away from the air, and the glucose 

 is added to absorb any oxygen which may be in the medium. 

 To increase our chances of obtaining this bacillus in pure cul- 

 ture, the material to be examined is to be heated to a tempera- 

 ture which will kill all developed bacteria, but which will not 

 be injurious to spores; the tetanus bacillus is the only 

 anaerobic organism with a spherical terminal spore which is 

 at all likely to occur in a wound. 



Method. The inoculations are to be made with a pipette. 

 If the pus which comes from the wound can be drawn up into 

 the capillary tube of a glass pipette such as is described on 

 p. 34, the material should be collected in this way. If this is 

 not the case, the wound must be scraped with a sterilized 

 platinum needle or other suitable instrument, and the material 

 thus obtained mixed with some boiled water (previously 

 cooled) and then sucked up into the pipette; the end of the 

 latter is then to be sealed in the flame, care being taken that 

 the material itself is not heated. 



Having filled and sealed the pipette, heat some water in a 



