DE 
re, 
METHODS 18 
inclined slide. Of course, all instruments, slides and covers were 
carefully sterilized in the flame of a spirit lamp. After the washing, 
the perithecium was crushed in a very small drop of water on the 
slide. This caused the spores and asci to escape in a bunch 
through the thin membrane. They could then be gathered up by 
a forceps or needle and transferred to the culture directly. Such 
precautions usually resulted in sufficient purity to insure a good 
crop of the fungus. The cultures were by no means pure but 
they were of sufficient purity so that the fungus could combat suc- 
cessfully with the bacteria. 
It was a long time before spores were obtained with sufficient 
cleanliness to enable me to grow them on agar-agar. Six succes- 
sive cultures were made in duplicate at one time on Polyporus with 
the utmost precautions ; but when the spores from these cultures 
were transferred to agar-agar the experiment was unsuccessful on 
account of the bacteria attached to the spores. At last, after study- 
ing the method of spore ejection, the securing of clean spores was a 
very simple matter. Cultures, as described above, were prepared in 
Petri-dishes or in the ordinary short stentor dish on paper or Poly- 
porus. When the perithecia became mature and began to eject 
their spores, the cover was removed, and the edges of the dish 
wiped carefully with a cloth moistened in a saturated aqueous solu- 
tion of corrosive sublimate. A new, freshly sterilized cover was 
now placed over the culture for twenty-four hours or less as the 
case required. Inasmuch as the asci stretch to the ostiolum 
before they rupture, the spores are ejected without coming in 
contact with the substratum or the perithecium at all. When 
caught on the freshly sterilized cover, therefore, they are clean 
and may be removed to the agar-agar culture with sterilized 
needles. If the operation is skilfully performed the culture will 
usually be free from bacteria. Sordaria fimicola was the species 
worked with mainly and the method proved well adapted. 
Much time has been spent in making preparations from agar- 
agar cultures. The whole process, however, has thus far proven 
as fruitless as it is fascinating. Excellent serial sections of Sor- 
daria fimicola have been obtained but it cannot be said that they 
show anything of importance. On this account it was deemed 
advisable to devise some method whereby the plants could be 
