1906] FULTON—CHEMOTROPISM OF FUNGI 99 
of the hyphae from that layer. Column I gives the average number 
of hyphae per hole in the layer from which the turning takes place; 
column II, the average number of hyphae per hole in the layer toward 
which turning takes place; column III, the percentage of turning. 
To determine whether this negative turning is due largely to 
chemical changes in the culture medium, beet decoction in which a 
fungus had grown was tested with that fungus. The sugar-beet 
decoction was diluted to one-third the strength of the stock solution. 
When a good amount of mycelium had been formed, the liquid was 
filtered under sterile conditions at room temperature. The filtrate 
was replaced in the incubator in the case of those species which had 
fruited, and was allowed to remain for twenty-four hours in order 
that any spores that had passed through the filter might germinate; 
it was then refiltered. In this way a practically sterile medium 
was obtained. One volume of this decoction was added to one 
volume of double-strength gelatin, and tests were made with this 
TABLE VIII 
* a B 
GrowTH TOWARD GELA-} GROWTH TOWARD GELA- 
tin Mape UP witH Tin Mane Up witH 
Bret DecocTIon IN _| FrEsH Beet DECOCTION. 
Wuicu Founeus Hap RO 
Grown 
I Il I It 
1, Doteytls vulgadis. 6.5002 si: 6.2 20 5-3 33 
; 15 3% 15 35 
II. Sterigmatocystis nigra............ 10 29 g-o 34 
19 27 17 37 
IiI. Penicillium MAUCUE ys 23a heen 8.0 23 12 3r 
18 22 28 23 
IV. Monilia sitophila........0.2+...- 8.0 22 9-0 26 
: 23 25 20 33 
¥..  Mucor-stolonifer. >... 2... 0. 33s 19 -32 22 38 
VI enricus fabaceus.. < 5c ys neces 49 24 50 32 
VIt. Coprinus micaceus.............- 31 24 43 30 
VIII. Daedalia quercina............+-- wo 468 35 31 
in comparison with control beet decoction in which there had been 
no fungous growth. The results are shown in Table VIII. Column 
I gives the average number of hyphae per hole; column II, the 
percentage of turning toward the holes. 
. The percentages for all of the fungi in this table, except Mucor 
