82 GENERAL BACTERIOLOGY 



CHAPTER III 

 TAXONOMY 



In order to become acquainted with a particular organism, to 

 differentiate it from its congeners or to assign it a definite place in a 

 system of classification, it must be studied under various conditions 

 and its characters determined as indicated in the following table. 



POINTS TO BE OBSERVED IN THE STUDY OF BACTERIA. 



The following scheme gives the most important points to be 

 noted in the description of an organism, together with some of the 

 more common descriptive terms suggested by Chester and others. 



MORPHOLOGICAL CHARACTERS. 



a. Form and arrangement: Spherical, micrococcus, single and 

 irregularly grouped ; diplococcus, streptococcus, tetracoccus, sarcina, 

 rods, single, in chains and in filaments ; spirals. 



5. Size. 



1. In terms of the micromillimeter ; breadth, average and ex- 

 treme length. 



2. In terms of human blood cells. 



c. Stain. 



1. Aqueous solutions: stains easily or with difficulty; uniformly 

 or irregularly. 



2. Special stains : Gram ; tubercle ; etc. 



d. Motility. 



1. Brownian movement. 



2. Vital movement: sluggish or active; rotary or direct; most 

 favorable temperature : age ; media : etc. 



3. Flagella: stained by Loeffler, Bunge or Van Ermengem's 

 method ; distribution : monotrichous, lophotrichous or peritrichous. 



e. Capsule: stained by Ziehl: Gram or Welch's method; most 

 favorable conditions ; broad or narrow ; present in serum, milk or on 

 agar streaks. 



