440 A MANUAL OF BACTERIOLOGY 



Plate on the bile- salt -agar plates ; incubate. 



Next Morning. Pick olt several non-lactose colonies (discrete 

 colonies wherever possible) and inoculate each colony into mannitol 

 and into ordinary broth. The number of colonies taken off will 

 depend on many factors -for example, (1) the number of white 

 colonies present, (2) the appearance of the colonies, (3) the 

 clinical symptoms of the case if known, (4) the appearances of 

 the stool. 



Evening of Same Day. After at least five hours' growth, 

 examine the broth tubes, preferably with dark ground illumination, 

 and record motility or non-motility. At the same time inoculate 

 an agar slope from each broth tube. 



Second Morning. The mannitol tubes are examined and the 

 results (acid and gas, acid only, or no change) recorded on the 

 corresponding agar slopes. 



1. If acid and gas and motile, test the corresponding slope with 

 P. G. mixture. A loop of culture is emulsified in 4 or 5 c.c. of 

 saline. Equal parts of this emulsion and the P. G-. mixture are 

 placed in a small " agglutination " test tube and kept at 37 C. 

 Examine the tube every hour and note if agglutination is taking 

 place. If so, test the corresponding emulsion with Paratyphosus A 

 serum, Paratyphosus B serum, and Gartner serum separately 

 (one dilution of each giving 1 in 400 in the final mixture). If 

 agglutination takes place with A serum, but not with B or Gartner 

 serum, the emulsion may then be tested up to the full titre of the 

 serum. 



2. If acid and gas and non-motile, no further steps need be taken, 

 but it must be remembered that a positive motility is final, while 

 a negative result may leave a certain element of doubt, in which 

 case it is wise to treat the culture as in 1. 



3. Acid only and motile. Test with the P. T. mixture. (Many 

 paratyphoid strains give little or no gas in the sugars they normally 

 ferment, and for this reason it is necessary to treat all cultures 

 giving acid only in mannitol (and motile) as possible paratyphoids 

 as well as typhoid.) If agglutination occurs, test further with 

 A, B, and T serums separately. 



4. Acid only and non-motile. Test with Y serum. 



5. No change on mannitol and motile. Discard for the time being, 

 or, if time permits, test further to determine whether the 



