Fungi at various Temperatures , &c. 277 
(b) Cultures grown for two days in air at 20°, then transferred to 5 0 , 
some in air, some in jo per cent, and 20 per cent. C 0 2 . 
Diameter of growth in 14 days after transference: 
Air. 10 °/ 0 C0 2 . 2o°/ 0 C0 2 . 
6.75 (100) 5.2 (77) 2.65 (39) 
In the latter case the retarding action of carbon dioxide is less than in 
the former, and this is obviously due to the fact that in the latter case, by 
germinating the spores in air at a high temperature, they were taken past 
the stage at which the retarding effect of carbon dioxide on them is greatest. 
A similar behaviour to that of Botrytis was shown by Monilia and 
Fusarium on apple gelatine. 
With potato agar, very diverse results were obtained with different 
fungi. Botrytis cinerea behaved in the same way on this medium as on 
apple gelatine. On the other hand, Penicillium and Sphaeropsis , after 
being grown for two days at 20° and then transferred to 5°, had their growth 
in air stopped entirely for a long time at the latter temperature, whereas 
they continued to grow slowly in 10 per cent. C 0 2 . This complicated 
behaviour is again without doubt associated with the fact that potato agar 
is a medium which lends itself with particular readiness to staling by 
development of alkalinity. 
C. Rate of Growth of certain Fungi on Fruit at different Temperatures 
and in different Concentrations of Carbon Dioxide . 
Experiments were carried out on the rate of attack of apple by 
Botrytis cinerea and Monilia cinerea , and of orange b y Penicillium glaucum. 
The fungi were introduced through artificial punctures in the skin of the 
fruit. Parallel series were run at 15 0 and 5 0 . Throughout the experiment 
it was necessary to open the containers every second day at the higher tem- 
perature and every four days at the lower temperature, and the atmospheric 
composition was made up afresh, this by reason of the respiration of the 
fruit. At the end of the experiment the amount of rotting in the case of 
apple was determined by weighing before and after removal of the rotted 
portion, and in the case of orange by counting the percentage of loculi 
affected by the fungus. The latter method did not appear to be very 
satisfactory. The following table gives the percentage of rotted tissue : 
Table IX. 
Air . 
IO°/n C0 2 . 
20 °/_ co 2 . 
At 1 5 0 . After io days. 
Botrytis cinerea . . 
14.6 
1.8 
0.4 
Monilia cinerea . . 
63*5 
23*3 
T 3*7 
Penicillium glaucum 
53 
52 
45 
At 5 0 . After 28 days. 
B. cinerea .... 
13-3 
1-0 
0.05 
M. cinerea .... 
45*9 
n*4 
1.0 
P. glaucum (35 days) 
50 
26 
