410 CHAELES SLA.TER. 



straightening movements seem to be due to the rolling motion 

 of a slightly curved organism round its longitudinal axis. 



By far the most noticeable characteristic is the highly re- 

 fringent nature of the poles of the cells. This refringence is 

 noticed in a very large proportion of the cells of a culture 

 examined at any stage of growth, and will be again re- 

 ferred to. 



On gelatine peptone growth takes place easily, though not 

 very rapidly, and does not produce liquefaction of the medium. 

 The growth forms a regular, raised, moist-looking, somewhat 

 glistening streak on the surface of the gelatine, and is fre- 

 quently surrounded by a white opalescence due to a deposit of 

 oxalate of calcium. The colour is pinkish or coral red, and 

 though this tint deepens during the first week the coloured 

 colonies are not preceded by any definite uncoloured stage, as 

 is the case in the Prodigiosus, &c. 



In a stab culture the growth takes place very scantily along 

 the needle track, and remains colourless. On the upper sur- 

 face the growth spreads from the point of inoculation, and 

 colours well. The organism is distinctly aerobic. 



On agar the growth is a little slower, and is rather more 

 vermilion in colour. The addition of carbohydrates to the 

 agar seems to make no difi'erence in either the rapidity or 

 colour of the growth. In the case of the B. rouge de Kiel, 

 M. Laurent (Ann. Inst. Past., iv, 465) has shown that the 

 colour is not produced in the presence of carbohydrates. The 

 addition of glycerine to the medium is, however, inhibitory to 

 the growth of the bacillus now described. At the most there 

 is a slight pink growth at the margin of the fluid which always 

 collects at the bottom of these tubes. 



In liquid media the growth is never copious, and the colour 

 extremely ill-developed. The media tried were ordinary 

 bouillon, bouillon with carbohydrates, and Pasteur's fluid with 

 and without sugar. The addition of sugar both to the bouil- 

 lon and the Pasteur's fluid certainly increases the growth and 

 assists the colour formation. The growth in these media 

 tends to collect at the edge of the fluid and to attach itself to 



