MILK ANOMALIES. 79 



(dj The Bacillus ruber is a long, thread-like, very 

 motile rod, which when isolated is grouped in threes or 

 fours and occasionally shows from two to four spores. 

 Upon agar a yellow layer is formed. It liquefies gela- 

 tine. Potato cultures are covered with a rusty red film. 



(e) Spirillum rubrum is a thick, clearly transparent 

 bacterium, having a regular spiral movement and is 

 provided at each end with a fiagellum. The long spirilla 

 exhibit slow motion while the short ones are actively 

 motile. Reproduction takes place by division. Spore 

 formation is doubtful. The spirillum grows between i6 

 degrees and 40 degrees, best at 37 degrees. Upon gela- 

 tine the growth is very slow, non-liquefying. In plate 

 cultures many small, grayish-red colonies the size of a 

 pin head are formed. In stick cultures, round, reddish 

 granular colonies are formed along the track of the 

 needle. Upon agar and blood serum a grayish white, 

 sharply defined layer is first developed, later producing 

 thick, rosy-red layers. Upon potato a moist glistening 

 layer, reddish in color, is formed. 



(f) Micrococcus cinnabareus is a large coccus often in 

 the form of a diplococcus and often grouped in threes and 

 fours, and does not liquefy gelatine. It grows very 

 slowly. Upon, plates, after about four days, the deep 

 colonies appear as pale brick colored points. In gelatine 

 stick cultures, white colonies are seen along the line of 

 punctures and upon the surface rose-colored buttons 

 develop, becoming dark red in time. 



(g) Sometimes the red color of the milk is due to col- 

 oring matter contained in the fodder or blood. 



2. Tellow Milk. Yellow milk is caused by the Bacil- 

 lus synxanthus (or Bacterium synxanthus Ehrenburg). 

 The micro-organism develops as an actively motile small 

 rod, which, when inoculated into sterilized milk, gives it 

 a citron yellow color. The yellow coloring matter disap- 



