534 
Chaiidhuri.—A Study of the Growth in 
so that when the last set of aerated ones were taken out and the last non- 
aerated ones put in, only another five days were required to complete the 
whole experiment. Every care was taken that the parent cultures were of 
the same generation and age. 
We find by studying Fig. io that by the end of twenty days maximum 
growth had taken place in the aerated ones, for at the end of twenty-five 
days there was no increase of growth over that of twenty days. 
In the non-aerated ones, however, maximum growth had not been reached 
by the end of twenty days, so they were carried on to thirty-five days. At the 
end of thirty days the dry weight still showed a certain gain, but by the end 
of the thirty-five days there was no further gain. So the maximum growth 
had taken place, and the total weight was much less than the total weight 
of the aerated ones. This shows the significant effect of aeration. 
Another set of experiments was carried out at the same time to deter¬ 
mine the actual difference in dry-weight production in a normal and half¬ 
normal medium ; it had been found previously, on the bases of the rate of 
spread of the mycelium, that there was no difference. These flasks were not 
aerated, and were examined on the fifth, tenth, twenty-fifth, thirtieth and 
thirty-fifth days. We find very little difference in growth between the 
tenth and twenty-fifth days, and after that there is no further increase in 
growth. The total weight is only about a third of the normal. When this 
result is compared with the result obtained by the method of increase in 
diameter it is clear that the increase in surface area of a culture on a solid 
medium does not give a satisfactory measure of the growth of this fungus 
in media of different concentrations. 
The following are the determinations of dry weight on Coon’s normal 
liquid medium at 21 ° C. The figures are in all cases the means of a number 
of cultures ; this number is given in the fourth column. 
Coon s Medium (Full Strength ). 
Dry Weight (grm.). 
Days. 
Aerated. 
Non-aerated. 
No. of sa?nples. 
5 
0-064 + 0-003 
0-037 + o-ool 
8 
IO 
0-203 + 0.004 
0.H5 ± 0.004 
8 
15 
0-336 (5 samples) 
0-205+0-006 
8 
20 
0-440 (5 samples) 
0-262 + O-OIO 
8 
25 
0.444 
0-294 
5 
30 
— 
0- 3 i 8±°- 00 3 
8 
35 
Coon s Medium 
°-3 1 8 ±0-003 
{Half Strength ). 
8 
5 
— 
0-037 
5 
IO 
— 
0-085 
5 
25 
— 
0-129 
5 
30 
•— 
0.130 
5 
35 
■— 
0-128 
5 
In Fig. io the curves for the growth of the aerated and non-aerated 
mycelia during the early period when there was plenty of food material 
show that the growth does not follow the compound interest law, as does 
