CLASSIFICATION 31 



genera and changes very few of those in more common use. 

 Possibly the greatest objection to this classification is the 

 use of the generic term bacterium to include a number of 

 species of pathogenic bacteria heretofore recognized as 

 bacilli.* 



MIGULA'S CLASSIFICATION OF BACTERIA. 



Families. 



I. Cells globose in a free state, not elongating in any di- 

 rection before division into 1, 2, or 3 planes 1. Coccqceae. 



II. Cells cylindrical, longer or shorter, and only divid- 

 ing in one plane, and elongating to about twice the 

 normal length before the division. 



a. Cells straight, rod-shaped, without sheath, non-mo- 

 tile, or motile by means of flagella 2. Bacteriaceae. 



b. Cells crooked, without sheath 3. Spirillaceae. 



c. Cells enclosed in a sheath 4. Chlamydobacteriaceae. 



1. COCCACEAE. 

 Cells without organs of motion. 



a. Division in one plane 1. Streptococcus. 



b. Division in two planes 2. Micrococcus. 



c. Division in three planes 3. Sarcina. 

 Cells with organs of motion. 



a. Division in two planes 4. Planococcus. 



b. Division in three planes 5. Planosarcina. 



* The different meanings attached to the words Bacillus and 

 Bacterium deserve notice. In two of the more recent systems of 

 classification the senses in which they are used have little in com- 

 mon. Lehrmann and Neumann apply the word Bacterium to all rod- 

 shaped forms in which spores are unknown (a point in regard to 

 which any day may bring a change in our knowledge), the genus 

 Bacillus embracing those in which spores have been found. Of the 

 manner of ciliation no notice is taken. Migula, on the other hand, 

 uses the term Bacterium for all non-motile rods, and Bacillus for 

 peritrichous species, the remaining motile forms, both lophotrichous, 

 monotrichous.and amphitrichous, constituting a new genus, Pseudo- 

 monas. 



