68 OrR—L&EAF GLANDS OF DIOSCOREA MACROURA. 
violet (Gram’s method), showed that it consisted of a pure culture 
of rod-shaped organisms, from 1.6m to 2.4u in length, and from 
64 to .8u in breadth. ‘They proved to be Gram positive, and it 
is interesting to note further, that the gentian-violet stain re- 
mained in the organism, after dehydration with amyl alcohol, 
but not after ethyl alcohol, resembling in this particular 
the similar reaction obtained by Harrison and Barlow on 
Pseudomonas radicicola. About 24 hours after inoculation, the 
organisms were actively motile in liquid media, and by careful 
staining, using the van Ermengen method * in a_ slightly 
modified form, it was possible to determine the presence of a 
single polar fageMuts on the bacterium cell. 
Stab, smear and plate cultures were also made on agar and 
palatin, by inoculation from liquid media. The agar was pre- 
pared by adding 2 per cent. of the substance to the nutrient 
solution containing saccharose; in the case of gelatin, the per- 
centage was a little higher. The agar cultures were incubated 
at 25° C, but those on gelatin, were, of necessity, developed at 
a lower temperature. It was found, however, that within certain 
limits, the difference in temperature did not appear to have much 
influence on the rate of growth. 
On saccharose agar, the colonies were round or oval, from 3-5 
mm. across. Raised above the substratum, they were hemis- 
pherical in form, sabaceous, faintly reticulated, and had a 
slightly fimbriated margin. On nutrient gelatin, the colonies 
were ochraceous, but otherwise they resembled those produced 
on agar. Smear cultures, on the other hand, rapidly became 
agglomerated to form nodulose masses (Plate CXCVIIL., fig. 2). 
In stab cultures, the growth was strongest at the point of 
entrance, and relatively weak internally, along the edges of the 
stab. 
On agar and gelatin, the colonies made their appearance in 
from 2-4 days after inoculation, the time taken varying with the 
composition of the medium kind as a source of infection. For 
example, cultures on nutrient gelatin, initiated by inoculation 
from solid media, became apparent in 24 hours, while, under the 
same conditions, cultures made from liquid nied coauined from 
4-5 days to reach a similar state of development. 
The culture of the organism, under artificial conditions, was 
maintained over a period of three months, at a mean temperature 
of 15° C, and during that time, cross peldctions between different 
media were carried out, the cultures, in all cases, remaining 
pure. 
That the organism is aerobic was suspected from its behaviour 
in stab cultures, and this was confirmed by the impossibility of 
* See Centr. fiir Bakt. xv. (1894), Pp. 969. 
