Culture of Verticillium albo-atrum , II. et Br. 
52i 
Fig. 1. Graph, showing the dry-weight production (in milligrams) of V. albo-atrum grown 
for sixteen days in Coon’s medium with varying amounts of maltose nnd asparagin. iM = normal 
amount of maltose, 1 A = normal amount of asparagin, 0-5 M = half the normal amount of 
maltose, &c. 
The Effect of Aeration and of Temperature on the 
Growth of the Fungus. 
Method. The various temperature conditions were obtained by means 
of incubators for the higher temperatures, viz. between 14 0 and 3o°C. For the 
lower temperatures, 5°-io° C., an automatically regulated refrigerator was 
used, and for ±2°C. a cool storage room. Experiments on aeration were 
first carried on with flasks of different capacity containing the same quantity 
of the liquid medium. It was found more growth took place in the flasks 
with greater capacity. Next, flasks of same size were taken, and were 
aerated once every day for a few minutes. This gave no better growth 
than no aeration. Successful results were obtained by aerating very gently 
but continuously. This was done by means of a glass blower attached to 
the water tap. About fifty flasks were aerated equally and simultaneously. 
The main tube was connected with a flask having five branch tubes; 
these being connected to small jars with ten branch tubes, which were con¬ 
nected with the flasks to be aerated. 
Throughout the course of experiment, data have been obtained both 
by measurement of the superficial growth on agar plates, and by determina¬ 
tion of dry weight; and an attempt has been made to determine how far 
the spread of a fungus on an agar plate is a satisfactory measure of its rate 
of growth. 
By measuring at regular intervals the spread of the fungus on an agar 
medium it has been found that there is little or no difference m the rate of 
spread between Coon s normal , half-normal, and quarter-normal medium , 
though there is a marked difference in the amount of mycelium produced (p- 534 )* 
