160 Dopce: METHODS OF CULTURE OF ASCOBOLACEAE 
the spores of this species to germinate at ordinary temperatures 
were unsuccessful. 
To determine the temperature used in such experiments more 
exactly, two Petri dishes, each containing about 50 c.c. of a decoction 
of heated soil, were heated in the oven after having been well inocu- 
lated with spores. The temperature of the decoction was deter-. 
mined by stirring with athermometer. The first reached 65° C. in 
‘25 minutes, the second 60° C. in 19 minutes. So far as I was able 
to find, every spore in both dishes germinated. Another dish con- 
taining a like amount of the decoction without spores was heated 
in the oven for 30 minutes. At the end of this time the oven 
temperature was 80° C. The door was then opened and the tem- 
perature of the decoction proved to be 72° C. Spores were now 
put into this dish, the gas was turned off and the oven closed. 
After five minutes the temperature of the decoction was again 
determined as before. The temperature had dropped only two 
degrees. These spores were certainly exposed for five minutes to 
a temperature of 70°-72° C. Seven hours later all the spores had 
germinated. 
In another experiment a beaker containing a decoction of 
heated soil was heated in a hot water bath to a temperature of a 
76° C. Spores were then introduced and the temperature main- 
tained at 75° C. for five minutes. Fully half the, spores germi- 
nated after six hours and only about one per cent had failed to 
germinate at the end of 24 hours. 
There is no doubt, however, that under certain conditions the 
spores of Ascobolus carbonarius may germinate without being 
exposed to such high temperatures. This is shown in the following 
experiment. A damp chamber containing a quantity of car 
bonaceous earth, upon which several ascocarps were growing, was 
exposed to direct sunlight for about two hours. Slides were placed 
above the ascocarps to catch the spores, and a few of these spores 
germinated in the film of water on the slide. A large number © 
the spores from these slides were wiped off into a heated soil decoc- 
tion and kept at room temperatures. The spores that had already 
germinated continued to grow, and in addition about 5-10 Pé& 
cent of the others germinated. It was found by further expeti- 
ments that liquid exposed to the sunlight under these conditions 
