450 
KEPOKT OF CHEMICAL LABOBATORY 
A bipolar 
bacterium 
in Hashab 
gum 
by passing them through the flame, I infected tubes of glucose gelatin with the fragments, 
and after 24 hours’ growth plated out nn saccharose potato agar. In every case 
practically a pure culture was obtained of the same organism. The colonies, after four- 
days’ growth at 35^ 0., had a puckered, dry appearance, and were rather greyish-yellow. 
The organism stained well with both Gram’s and Lolfler’s stain. It was noir-motile, and 
exhibited well-marked bipolar staining (Fig. 218). From the original plate cultures 
1 sub-cultivated on the same medium, and then on the special medium containing laevulose 
and tannic acid recommended Iry Greig Smith for the production of slime. I found that 
the bacterium from Ilashab did not grow at all well on this medium, but on a moditied 
medium without tannin it grew well and produced a slime. Greig Smith mentions 
that this special medium for B. acacue is not suitable for all gum-producing bacteria. 
Having found a medium which promised fairly well for the production of slime, I proceeded 
on a larger scale, but unfortunately lost all the cultures, plates, etc., when the laboratory 
was destroyed by fire, and have been unable to replace them. I think, however, that there 
can be no doubt that the same bacterium was isolated from several gum-bearing branches, 
and that it was actually present in the bark, sufficient ])recautions being taken to prevent 
accidental contamination. 
In concluding this Report, I have to acknowledge my great indebtedness to 
Dr, Balfour for much assistance and advice in connection with the bacteriological work, 
which I much regret having lost at such an interesting stage. I am also very much 
indebted to Dr. Beam for advice and help in the chemical part of my work. lie has 
given me the fullest information obtainable on all points connected with the collection 
of gum, and also the physical properties, such as hardness and viscosity, which are 
fully dealt with in his Report. 
