1916] 
GILMAN—CABBAGE YELLOWS 69 
not show the duration of temperature in any one day. The 
records themselves, while they cannot be presented here, show 
this increase more markedly—for the length of time of the 
higher temperatures increased—as the spring gave way to 
summer conditions. In any case the cooler condition pre- 
vented the attack of the fungus for at least a month. 
In the experiment in which the flats were placed on the 
north side of the potting-shed, three flats of diseased soil 
were used. Two were placed on the north side of the potting- 
shed, and the third in the warm house. "The flats were planted 
April 9, and yellows appeared in the flat in the greenhouse 
on April 17, while none was found, up to May 26, in the flats 
kept outside. Soil temperatures covering this period are 
shown by the curves in fig. 21. 
/0 /2 14 /6 /8 20 28 24 26 28 J 2 4 8 /o ІР 14 /6 |8 20 
EE) TH HFE BESESRERRbRSER 
EC rt r1 
EC) IN | ri | 
ПП LI LI D 
EC H TI Cl 
ТТЕП H IN в! 
EC LH ri 
d 3o mmmmm HH —- E | —— | БЕКЕБЕЕЕГЕКЕТІ 
5 PH Н H HHH 
< ГЕ BEREEE г 
Er, 2 AR Н H \ ааа! 
+ an a CONC " 
© 20 SEH в = == E GER e 
к? иии TI r Н H " 
5 222224 H H Е 
ma Cl im) g! и! =" 
Q Se EECH AHH H S 
% Sierck) LH Li O O LI a 
% 10 CL ri Ц ишн шша жож еш) 
< ва! | H A E 4 rH LLLELELALLTI 
Ov аа! N Г] MI VI Hu Co 
Y rH ПИТА Ini M H Coo 
ma Hi LX ІШ! N H COCO eer ШІ 
Li H LI H I H этн шт ДАЛ ТІТТЕГІТІІТТІІ 
су cot H LI H а! H LLLELEEELLELLLELELELLELLTU 
Hi а! г ai H H LLLLELHILLLCELLLEEELHLELLETTET II 
LH Г LI T$ rH и! SURES PORES Re | 
Fig. 21. Comparison of soil temperatures in House Пе with those on north side 
of potting-shed, April 10-May 20, 1914; House Пе, broken line; north side of 
potting-shed, solid line. 
Further work was undertaken at the Missouri Botanical 
Garden to try to determine the lowest point at which the at- 
tack may occur. To this end two glass incubators were set 
up, and the temperature was controlled by an electric thermo- 
regulator, so that it varied but a degree or two at the most. 
One incubator was set up in the laboratory at a west window, 
and the other was placed on the north side of the building. 
The temperature of the incubator in the laboratory was kept 
