Fischer . — The Biology of A rmillaria mucida , Schrader. 519 
Finally, for the permanent cultures in which the life-history was to 
be traced, the substratum used was chiefly bread moistened with water only, 
or with a decoction of horse-dung. Beech twigs and small cubes of beech 
wood were also made use of. 
The permanent cultures were in bulb or Erlenmeyer flasks. 
All glass receptacles were sterilized in the dry oven up to a tempera- 
ture of 165° C. Bread and beech twigs or cubes were similarly heated 
in the dry oven, the bread until it was toasted a rich brown, and subse- 
quently moistened. 
Liquids were placed in the steam sterilizer for at least one hour after 
strong steaming had begun on not less than three consecutive days. 
In addition, in order to exclude bacteria, a little acid was added to the 
liquids. 
The manual methods employed do not essentially differ from those 
advocated by Brefeld ( 3 ), so they need not be described in detail. It will 
be sufficient to add that I took every care to avoid intrusion by foreign 
bodies and to keep the cultures absolutely pure. Cultures in which 
impurities — Bacteria, Penicillium , Mucor — appeared were promptly de- 
stroyed. The flasks were stoppered with cotton-wool, which was invariably 
burnt in a Bunsen flame before removing from or replacing in the mouth of 
a flask. The interior of the neck of the flask was similarly subjected to 
the Bunsen flame. 
Altogether the following cultures were instituted : 8 hanging drops in 
moist chambers; 25 Petri-dish cultures in jelly; 12 on jelly or liquids 
in flasks ; 6 on twigs or wood cubes ; 2 on bread in large crystallizing 
dishes under bell-jars ; 23 in flasks on bread ; and 4 in liquids in test-tubes. 
The meat and malt extract jelly was made up as recommended by 
Professor von T ubeuf as follows : — 
Liebig’s meat extract 
Malt extract * 
Gelatine 
Citric acid . 
Water 
. 10 gr. 
20 gr. 
. 100 gr. 
4 to 5 gr. 
. 1 litre. 
In some cases a decoction of horse-dung was added to the above, both 
with and without the gelatine. 
Two other solutions were made up as follows : — 
Peptone 
, .25 gr. 
Dextrose . 
... . 1-25 gr. 
Potassium phosphate . 
• -°75 gr- 
Magnesium sulphate . 
• -o °5 gr- 
Citric acid . 
• 1 gr- 
Water « 
. 250 cc. 
