66 LABORATORY GUIDE IN BACTERIOLOGY 



3. Plates are to be described only once after 24 or 

 48 hours, according to growth. Make notes in column 

 7 for agar plate; in column 8, for gelatin plate. Make 

 sketches in the margins reserved for this purpose. 



4. The growth on the media i, 2, 3, 4, 5, and 6 is 

 to be described fully according to the outline in the 

 spaces under 24 hours. In the spaces under 48 hours 

 and 6 days note only the changes from the first descrip- 

 tion. 



5. Make sketches frequently and accurately, espe- 

 cially from milk and gelatin media, and any other 

 noteworthy growth, in the columns reserved for this 

 purpose; also a sketch of each organism from part of a 

 field under the microscope. 



These directions for filling out culture charts are 

 applicable in the described manner to studies of cul- 

 tures furnished by the laboratory. For determining 

 any species of unknown bacteria, original researches 

 must be made to cover all points, without the possi- 

 bility of gathering this information from textbooks or 

 references. On the accuracy of observation and de- 

 scription depends the success of bacteriological work 

 and species determination. It is frequently neces- 

 sary to employ special media, or inoculation of animals, 

 or such biological reactions as the agglutination test, 

 to determine what species one is dealing with. 



The student will do well to familiarize himself 

 with all directions and explanations given in this and 

 the previous chapters. Find a characteristic for each 

 item mentioned; otherwise the descriptions will be 

 incomplete; and follow the instructions for routine 

 work with all possible accuracy. 



