CONTRIBUTIONS FROM THE WISLEY LABORATORY. 73 
having regard to the result obtained by Mr. Hewitt that bulbs are 
killed by soaking for one hour at a temperature of 120 0 F., it was decided 
not to exceed this temperature. A preliminary experiment was 
conducted by soaking bulbs for one hour at a temperature of no° F., 
and it was found that the eelworms in the centre of the bulbs were 
unaffected by this temperature. 
The temperature of the centre of the bulb at the end of one hour 
was 9 0 F. below that of the water in which they were soaking. At 
Table IV. — Reichert Thermal Stage Experiments. 
Temperature. 
110-111 0 F. 
H9-I20°F. 
126-127 0 F. 
128-129 0 F. 
i3i-i 3 2°F. 
I35-I36°F. 
Length of Time Eelworms Lived. 
45 minutes 
15 
11 
9 
9 
5 
the end of four hours the centre of the bulb was the same temperature 
as the water. 
It was decided to experiment with three ranges of temperature, 
viz. iio°-iii 0 F., ii4°-ii5°F., and H9°-i20° F. ; both healthy and 
diseased bulbs were given the same treatment and were allowed to 
remain soaking for 1, 2, and 4 hours. The temperature was regulated 
by means of a thermostat, and the vessels containing the bulbs were 
immersed in an outer bath of water. The results of these experiments 
are as follow : 
Table V. — Effect of Soaking Bulbs in Warm Water. 
Temperature of 
Water. 
Period of 
Soaking. 
Effect on Growth of Healthy 
Bulb. 
Condition of Eelworms in Bulbs. 
iio 0 -iii°F. 
1 
no injurious effect 
live eelworms found 
no°-iii e F. 
2 
very slightly retarded 
an occasional eelworm 
found alive 
iio°-iii e F. 
4 
slightly retarded 
no eelworms found alive 
ii4°-ii5°F. 
1 
badly damaged 
live eelworms found 
H4°-ii5° F. 
2 
bulbs killed 
no eelworms found alive 
H4 0 -ii5°F. 
4 
» > 
>> >> 
H9°-i2o° F. 
1 
>> >) 
H9°-i2o°F. 
2 
»> j} 
H9°-i20° F. 
4 
> > 
>) )> 
From these experiments it appears that a very high temperature 
is not necessary in order to kill the eelworms in affected bulbs. The 
bulbs, also, are readily damaged by heat or their growth retarded. 
It appears that soaking the bulbs for a period of from 2 to 4 
hours at a temperature of no° F. affords the best method of con- 
trolling the eelworms in affected bulbs. The effect of soaking healthy 
bulbs in water at this temperature for a period of from 2 to 4 hours 
