PARASITIC ON PELLIA EPIPHYLLA. 105 
Hypocrea*, long known as a saprophyte, but in the present 
instance apparently associated with a definite disease. 
Iremoved a few spores from spore-clusters on the host by 
means of freshly drawn glass needles, and sowed them in 
hanging-drops of a nutrient solution made by boiling pieces of 
thallus and filtering-off and sterilizing the extract thus obtained. 
(I had already made trial cultures, and had found that the spores 
grow readily in drops of the juice squeezed out of the crushed 
thallus, diluted, but not sterilized.) Before entering into details 
I may say that other cultures were made in flasks, tubes, and 
hanging-drops of sterile 
(1) cold-water extract of the thallus; 
(2) boiling-water ,, » 
(3) nutrient gelatine, consisting of (1) containing gelatine ; 
(4) » » » (2) » » 
In addition I sowed spores, taken from the spore-clusters on 
the host, on fresh, healthy pieces of thallus, some of which were 
kept in the dark room, while others were allowed to remain as 
controls in the laboratory. Finally, I sowed spores from pure 
eultures on pieces of thallus, some from the Filmy Fern house 
and in other cases on thallus obtained from a brook in the neigh- 
bourhood, where it grows wild and whence the original stock of 
thallus had been brought. 
My method of preparing the medium was as follows :—Pieces 
of thallas were thoroughly pounded in an earthenware mortar 
with a small quantity of clean white sand, and the whole then 
boiled in a beaker for about half an hour ; then strained and 
filtered and added to well-soaked gelatine. The resulting nutrient 
gelatine was filtered and sterilized. Two-ounce flasks were pre- 
pared with a layer of nutrient gelatine about 1 cm. deep; and 
test-tubes containing 3-5 c.c. were, after complete sterilization, 
inclined, 80 that at the final cooling as large a gelatine surface as 
possible was obtained. Both flasks and tubes were infected by 
means of freshly drawn glass needles, and a daily record kept of 
all ehanges observed. The normal course of events was as 
follows :—In about 24 hours the point of infection could be 
point of in 
o Be hod ma see Saccardo, Sylloge, vol. iv. p. 59; Rabenh. Pe 
‘Handbuch? iv re lasne, ‘Select. Fung. carp. vos stew P n" 
Berkeley's “Outlines? ; Harz, in Bull. Soc. Imp. des Nat. Mose. xiv. p. , 
» 857 ; :e's * Bri i? vol. ii. p. 774; Massee's 
Fungus Flora; iii. p. Lm 5T ; Cooke's * Brit. Fungi,’ vol. 11. p. 4 
