DopGE: METHODS OF CULTURE OF ASCOBOLACEAE 157 
and stirring the agar with a thermometer it was found that when 
this oven had been heated to 75° C. during a period of 20 minutes 
the agar in the Petri dishes was at about 60° C. When water was 
substituted in place of the agar the plates in the front row on the 
asbestos shelf were only at about 55° C. while those on the rear 
row were at 60°-65° C. The evidence obtained, however, shows 
conclusively that the application of heat is an effective stimulus 
to spore germination. 
The data for some thirty experiments, in which one hundred and 
ninety inoculations were made in as many plates, are summarized 
in TaBLE II. The per cent of germination was determined by 
noting approximately how many spores of given groups failed to 
grow. 99 per cent means that ungerminated spores could not be 
found, 
The plates in no. 20 and no. 21 were treated exactly alike but 
only ro per cent of the spores in the first (no. 20) germinated, while 
practically all the spores in the second (no. 21) did so. The spores 
from no. 20 were obtained from dung collected in the field during 
very cold rainy weather. The apothecia and spores were very 
much paler than is normally the case. The plates of no. 21 were 
inoculated with spores from apothecia developed from dung that 
had been gathered the previous year and stored in the laboratory. 
When an artificial culture has produced a number of ripe 
apothecia the spores may be seen lying all about on the surface 
and within the medium. These spores do not germinate even 
though the medium is well supplied with moisture. Three such 
cultures were heated to 60°, 65°, and 70° C. respectively. None 
of the spores in the medium germinated. It was not a case where 
the required nutrient was lacking, since many of the spores on the 
Covers of these same dishes germinated in the film of water after 
being heated. No second crop of this species ever appears in damp 
chamber cultures. It may be, however, that certain toxic sub- 
stances that inhibit germination are given off during the growth 
of the mycelium and apothecia. Spores from these same dishes 
Were used to inoculate controls containing fresh media, and in 
these controls germination was abundant. 
To determine the effect on germination when hard agar is 
used, a medium was made up with a much smaller percentage of 
