384° OLDENBUSCH: STIMULATION OF PLANTS 
A small drop of this gelatine was put on a clean cover glass 
and inoculated with fungus spores. After inverting the cover 
glass, and sealing on to the glass ring the slides were left standing 
at room temperature under a bell-jar containing moist filter 
paper to prevent slides from drying up. After some hours, 
slides were examined microscopically for germination, and where 
possible the germination-tubes were measured by means of a 
standardized micrometer eye-piece. 
According to TaBLe III. solutions of carbon disulphide in 
nutrient gelatine varying from M/16,000 to M/40,000 in con- 
centration, stimulate spores of Rhizopus nigricans and Sterig- 
matocystis nigra to germinate sooner than in the same media 
but without the CS,. The point of greatest stimulation lies 
between the M/32,000 and the M/40,000 solutions. 
In another type of experiment with Sterigmatocystis spores, 
the stimulation of growth was measured by the increase in dry 
TABLE III 
AVERAGE GROWTH IN MICRONS OF IO GERMINATION TUBES OF FUNGOUS 
SPORES, INOCULATED ON NUTRIENT MEDIA TO WHICH CS, HAD BEEN ADDED 
Ruizorus NIGRICANS 
Exp. A. 
No. - M/800 M/8,000 M/16,000 M/22,000 M/32,000 M/40,000 Control 
hou 
‘Si 10.6 11.9 59-9 Over 300 oOver300 Over300 250. 
Exp. B. 
13% no no no no 6.7 52.6 no 
15 no no no 13.9 16.4 83.2 no 
18 5.0 no no 70.0 50.4 Over 300 45.9 
20144 = 26.9 no 9.5 103.9 76.7 over300 59.5 
Exp. C. 
13 29.7 57-4 over300 139.2 over300 over 300 no 
14 59.6 over ae Over 300 oOver300 over300 over 300 no 
17 over 300 ce ae “c a“ at ae “ es ae 98.6 
Exp. D. 
13 129.6 . 202.6 mca 13.2 8.1 10.1 no 
313.0 — 22.7 24.1 46.5 14.8 
18 over300 over300 —— 44.3 73-6 79.3 44-5 
Exp. E 
14 67.5 68.3 —— 20.4 39.2 21.0 10.9 
17 101.6 148.1 — 62.2 84.3 43-4 25-5 
—_— 91.6 96.9 88.2 52.6 
19 127.4 over 300 
