Notes . 
153 
and drought acting on the leaves is the same as in terrestrial plants ; 
there is a distinct elongation of all the cells in a direction at right 
angles to the surface ; the cuticle is better developed, and the leaf as 
a whole is thicker and smaller. 
PERCY GROOM, Oxford. 
ON THE RESISTING VITALITY OP THE SPORES OP 
BACILLUS ME G ATERIUM TO THE CONDITION OP DRY- 
NESS. During the autumn of 1885 and spring of 1886 I was 
engaged with bacterial studies in the laboratory of my friend Pro- 
fessor M. Hartog of Queen s College, Cork. He had brought from 
Strasburg the dry spores of a cover-glass culture of B . Megateriwn , 
prepared by Professor De Bary in his laboratory on August 1884. 
From this, in the early spring of 1886, we succeeded in raising pure 
cultures with nutrient gelatine, and we afterwards kept the Bacillus 
under observation in good condition for several months. The usual 
method of cultivation practised by us was that of the hanging-drop, 
on cover-glasses, inoculated from gelatine-colonies, and then inverted 
on a damp filter-paper-cell which was placed on an ordinary slip, and 
kept at the temperature desired in a damp chamber ; we found the 
Bacillus to develop favourably in a solution of filtered milk and water 
with a little added glucose ; or in a 50 % glucose solution with a trace 
of Liebig’s extract. Many of our cultures so prepared were care- 
fully dried off and distributed among the botanical and pathological 
laboratories of Great Britain and Ireland. 
On March 1886 I prepared a special culture of B. Megaterium for 
public observation at a conversazione held in the Art Schools at 
Cork. A young pure cover-glass culture was chosen and transferred 
to a cell of millboard saturated with paraffin-wax, the edges of the 
cover-glass being luted on with warm paraffin-wax, with the object 
of keeping the cell air-tight. The cultivation was on view for three 
successive evenings, and appeared quite pure : the Bacillus showed 
characteristic motion, which lasted nearly two days, when it settled 
down, and gradual spore-formation became visible : on the third 
evening the spores were mature, and the thin film of liquid hanging on 
the cover-glass appeared to have in greater part evaporated. 
I carefully preserved this cultivation among my other slides, and 
had occasion to examine it several times at long intervals, till Novem- 
ber 1890, when, having offered to demonstrate a lecture on decompo- 
