120 REPORT OF COMMITTEE 



and examine at various ages. A culture of a large rod should 

 not be recorded as a non-spore-former unless all these tests are 

 negative. 



Capsules. An organism should not be recorded as having 

 capsules unless they have been actually stained by one of the 

 methods of capsule-staining described in bacteriological text 

 books. 



Irregular forms. Forms that differ from the typical shape for 

 the organism (i.e., ''involution forms/' etc.) such as branching 

 forms, clubs, spindles or filaments should be noted and sketched. 



Special stains. In making the Gram or Neisser stain and in 

 testing the acid-fast properties of the organism, directions given 

 in any reliable laboratory manual may be followed. 



Sketches. Drawings of all the morphological characteristics 

 should be made on the blank spaces on the chart to the right of 

 the descriptions. Both typical and atypical forms should be 

 sketched, using care to designate which are typical. 



CULTURAL CHARACTERISTICS 



Cultures for the study of cultural characteristics should be 

 incubated at 37°C. in case of organisms of series I and III, and 

 at 25° in case of organisms of series II and IV, except that gela- 

 tin cultures should be incubated at 20°. Room temperature 

 may be used in place of 25° at certain seasons of the year; but 

 if a minimum thermometer shows that the temperature falls 

 below 22° during the course of the work, note should be made 

 of the fact. On the day when good growth first appears the 

 proper descriptive terms on the card should be underlined; after 

 subsequent study, the changes should be noted in the space 

 provided, and sketches of the different stages should be made. 



PHYSIOLOGY 



Liquefaction of gelatin. Old method. The method in most 

 common use is to hold gelatin stab cultures six weeks at 20°C. 

 Plain gelatin should be used. 



