CLASSIFICATION OF BACTERIA 25 



due to protozoa. The apparently specific diseases for which 

 an etiological factor has not been demonstrated are grouped to- 

 gether after those of recognized cause. Finally, a few affections 

 resulting from animal parasites are appended for aid in differ- 

 entiation from infectious diseases that they somewhat resemble 

 in their lesions. 



§17. Migula's classification of bacteria. The genera 

 are included- of the first three families only. 



FAMILIES. 



I. Cells globose in a free state, 

 not elongating in any direc- 

 tion before division into 1,2, 

 or 3 planes i. Coccacese. 



II. Cells cylindrical, longer or 

 shorter, and onl}- dividing in 

 I plane, and elongating to 

 twice the normal length be- 

 fore the division. 



(i) Cells straight, rod-shaped, 

 without sheath, non-motile, 

 or motile by means of fla- 

 gella 2. Bacteriaceae. 



(2) Cells crooked, without sheath. 3. Spirillacese. 



(3) Cells enclosed in a sheath 4. Chlamydobacteriacege. 



(4) Cells destitute of a sheath, 



united into threads, motile 

 by means of an undulating 

 membrane 5. Beggiatoacese. 



GENERA. 



I . Coccacecs. 



Cells without organs of motion. 



a. Division in I plane i. Streptococcus. 



b. Division in 2 planes 2. Micrococcus. 



c. Division in 3 planes 3. Sarcina. 



Cells with organs of motion. 



a. Division in 2 planes 4. Planococcus. 



b. Division in 3 planes 5. Planosarcina. 



