REPORT OF COMMITTEE ON DESCRIPTIVE CHART 131 



INVIGORATION OF CULTURES 



Provided a medium can be found upon which the organism to 

 be studied grows vigorously, it should always be invigorated be- 

 fore study, even though freshly isolated from its natural habitat. 

 The procedure to employ is as follows : 



Prepare duplicate sub-cultures in standard glucose broth, and 

 on standard agar slopes, placing cultures of each at 37° and 25°C. 

 On the basis of the resulting growth the organism falls into one 

 of the following series: 



Series I. Organisms which produce good growth (surface 

 growth, distinct turbidity, or heavy precipitate) in twenty-four 

 hours at 37° in glucose broth. 



Series II. Organisms which do not produce good growth in 

 twenty-four hours as above, but do in forty-eight hours at 25° 

 in glucose broth. 



Series III. Organisms which do not grow well in glucose broth 

 but do produce good growth on the surface of agar in twenty- 

 four hours at 37°. 



Series IV. Organisms excluded from the above groups but 

 which produce good growth on the surface of agar in forty-eight 

 hours at 25°. 



Record the series number on the chart at the proper place and 

 proceed with the invigoration by inoculating into another tube 

 of glucose broth for organisms of series I and II, or of standard 

 agar for organisms of series III and IV. Incubate this tube at 

 the temperature, and for the time, called for by the series in 

 which it belongs; then transfer from this tube to a third tube and 

 incubate as before. From this third culture make a gelatin or 

 agar plate and incubate at the temperature previously used until 

 colonies of sufficient size for isolation are obtained. Transfer 

 from a typical colony to one or more agar slants and incubate for 

 one day at 37° or for two days at 25° according to the temperature 

 relation of the organism studied. 



In case the organism does not produce vigorous growth on 

 either of these media at either temperature, it should be invigor- 

 ated with any medium and at any temperature known to be 



