28 
Research Bulletin No. p 
suggested by Hasselbrixg (14) was followed. Erlennieyer flasks 
of 200 cc. capacity were used with 50 cc. of solution per flask. The 
solutions in the flasks were autoclaved for 10 minutes at 7 lb. 
pressure, and then inoculated by means of sterile pipettes with a 
drop or two of spore suspension. The cultures were killed by 
adding 10 cc. of 10 per cent HCl to each flask. The cultures 
were then filtered ofi:' on tared Gooch crucibles prepared with 
asbestos, washed until acid free, and brought to constant weight in 
a Freas electric oven at 100° C, and the dry weight determined. 
It was found impossible at times to filter luxuriant cultures of 
F. oxysponim by this method, because of the tenacity with which 
this organism holds water. Consequently they were filtered on 
soft filter paper, transferred to tared Gooch crucibles, dried, and 
weighed. The other organism holds water with little tenacity and 
filters with ease. 
In all of experiments gi\en below the following stock mineral 
solution was used: 20 gm. XH^XO., ; 10 gm. KH^PO^; 5 gm. 
MgSO^ per 1000 cc. H./"). When carbohydrates were employed, 
TABLE I 
Dry weight (in milligrams) after 20 days' growth in potato extract 
medium; room temperature 
! Fusarium oxysporum 
Temperature 
I 
35° 
30° 
25° 
12° 
l°.ll* 
— l°.ll* 
Flask 1 
Flask 2 
40 
47 
61 
49 
55 
78 
86 
73 
63 
68 
80 
70 
64 
66 
68 
66 
62 
86 
Flask 3 
Average 
62 
86 
Fusarium trichothecioide 
Temperature 
1 35° 
1 
30° 
25° 
12° 
l°.ll* 
— l°.ll* 
Flask 1 
Flask 2 
0 
0 
0 
0 
0 
0 
0 
0 
60 
64 
65 
63 
87 
100 
147 
111 
146 
83 
Flask 3 
Average 
146 
83 
*For 20 days (no growth), then at 25° C. for 25 days. 
