1g2 BOTANICAL GAZETTE [SEPTEMBER 
suggested by HASSELBRING (14) was followed. Erlenmeyer 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 tocc. of ro per cent HCl to each flask. The cultures 
were then filtered off 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. oxysporum 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 given below the following stock mineral 
solution was used: 20 gm. NH,NO,; 10 gm. KH.PO,; 5 gm. 
MgSO, per tooo cc. HO. When carbohydrates were employed, 
TABLE I 
DRY WEIGHT (IN MILLIGRAMS) AFTER 20 DAYS’ GROWTH IN POTATO EXTRACT MEDIUM; 
ROOM TEMPERATURE 
Pr 
Temperature 
35° 30° 25° 12° x: xi" —1°11* 
marae Or Se 40 55 63 64 62 86 
a eas 47 78 68 66 Bring) Vora eS 
Fla a. a ee 61 86 80 (See cere Pe Pee 
hee hee 49 73 7O 66 62 86 
FUSARIUM TRICHOTHECIOIDES 
Temperature 
35° 30° 25° 12° aS be —t¢11* 
fe ee senna ° ° 60 87 146 83 
Flask 2 ° ° 64 100 i eee oe 
ye ee ° ° 65 bey ne ee Pr 
Ace ° ° 63 III 146 83 
*For 20 days (no growth), then at 25° C. for 25 days. 
