244 ^IMPORTANT VARIETIES OF FISSION-FUNGI. 



readily staining polar bodies at the ends of the rods, while 

 the middle remains unstained. Young rods are always 

 actively motile. Concerning non-motile forms, see under 

 Baci aerogenes (19, vin, ix). 



Staining Properties.' Easily stained, even with cold 

 solutions, by ordinary methods. It is not stained by 

 Gram's method. 1 



Form and Arrangement of the Flagella. 2 Most 

 authors, like ourselves, have found the flagella similar to 

 those of the Bact. typhi, but a little less numerous i. e., 



4 to 8 peritrichous, long, slightly wavy flagella. Stocklin 

 has found very great variation in individual " varieties " 

 of Bact. coli in this respect ; some correspond to the 

 description given above, a greater number possess 1, 3, or 



5 flagella, a few generally only a single flagellum at the 

 end. In the very painstaking work of Kemy and Sugg 

 the flagella of the B. coli are described as somewhat 

 shorter than in the Bact. typhi, and very fine (C. B. xiv, 

 70). We cannot entirely confirm this, for among the 

 different varieties (about twelve) which were stained by 

 us there were some with very long flagella. Sometimes 

 the flagella extend outward from a colorless capsule. 



Relation to Oxygen. Grows best as aerobe, espe- 

 cially upon nutrient media containing sugar; anaerobically 

 it does not grow quite so well, and still more poorly when 

 sugar is absent. It grows also in C0 2 , but not quite so 

 well. 



Requirements as Regards Temperature and Nutri- 

 ent Media. It grows rapidly at room temperature and 

 very well at 37, is satisfied with the various nutrient 

 media, tolerates quite strong acid reaction, but in nutrient 

 media containing sugar it not infrequently produces more 



1 The statement of Alexander Schmidt (C. B. xm, 761) that by 

 cultivating upon nutrient media containing fat the Bact. coli acquires 

 the property of staining by Gram's method, we could not verify, and 

 no more could Jacobsthal (H. R., 1897, 849). 



2 We group provisionally the forms which have only one or a few 

 polar flagella, instead of a large number of peritrichous flagella, 

 as special "forma polaris " Lehm. and Neum. (compare p. 252). The 

 non-motile forms we place under Bact. aerogenes. 



