FAMILY BACTERIACE^E. 193 



Since it is not to be doubted that Ali-Cohen saw motion and Loffler, 

 Migula, and others have stained long flagella, so we must now conceive 

 of our Micr. agilis only as a Micr. roseus, which once possessed flagella, 

 and then lost them. 



We believe our observation is of primary significance in classifica- 

 tion, as many investigators consider the flagella as a very important 

 and constant differential aid. Migula has formed a genus planococcus 

 for the Micr. agilis ; without our observations we should have as- 

 sented. But being in possession of this, it seems to us that our con- 

 ception is at present more natural than the other possible one, namely, 

 that the Planococcus agilis, because of the loss of its flagella, can no 

 longer be distinguished from the Micr. roseus, but that it still belongs 

 to a different genus. 



Micr. cerasinus (List.) (Lehm. and Neum.). 



Micrococcus cerasiiius siccus List. (Adametz, " Bakterien der Trink- 

 und Nutzwasser"). 



Very small cocci of 0.3 //. Upon gelatin cherry-red, without lique- 

 faction. Upon potato, dry, spreading deposit of cherry-red color. 

 Pigment insoluble in alcohol and ether; whether in water, we do not 

 know. 



Micr. erythromyxa (Overbeck). 



Compare Sarcina erythromyxa, page 162. Sarcina formation seems 

 to be entirely absent at times. 



Micr. cyaneus (Schroter) (Cohn). 



Forms a cobalt-blue deposit, pigment soluble (!) in water, turns 

 red with acids, blue returns with alkalies. Schroter also described a 

 variety of this, pseudocyanea, that at first produced verdigris-green, 

 either remaining so or later becoming bluish-green to blue. So far 

 it has not been further described. Obtained from the air in Breslau. 

 Kegarding the Micr. cyanogenus, consult Pammel and Combs (C. 3. 

 L. II, 764). 



IL FAMILY BACTERIACEAE (ZOPF EMEND. 

 MIGULA). 



(For diagnosis of family, see p. 124. ) 



i. Bacterium. 1 



Cells at least one and a half, but usually from two to 

 six, times as long as broad, straight or. bent in a plane 



1 The "bacteria" of tuberculosis and diphtheria and those closely 

 related to them are to be looked for in Appendix I, Actinomycetes 

 (compare *p. 127). 

 13 



