342 
LON A. HAWKINS AND NEIL E. STEVENS 
ference between these two groups is in the transmission of the shorter 
wave-lengths. In figure 4, which shows the curves of spectral trans- 
mission of E. parasitica, E. fluens, E. fluens mississippiensis, and E. 
singularis grown in pure culture, it is apparent that very little of the 
light of a wave-length below 480 iifx is transmitted. From this point 
the percentages of transmission increase with increase in wave-length. 
^/O420 440 460 ^80 300 520 5'10 S60 5&0 600 620 e^^O 660 680 yOO ?'207^0 
Fig. 5. Curves of percentage of spectral transmission of alkaline alcoholic 
extracts of E. tropicalis (T) from pure cultures on rice, E. parasitica (P), stromata 
from chestnut, E. gyrosa (G), stromata from beech, and E. singularis (S) stromata 
from chaparral oak. The curves were plotted with the percentage of light trans- 
mitted as ordinates and wave-lengths of light in ixix as abscissae. 
The curve of the percentages of transmission of the alkaline extract 
from the mycelium of E. tropicalis in pure culture shown in figure 5 
is an example of the other type of curve. With this solution about 
52 percent of the light of a wave-length of 420 ^/z passed through and 
60 percent of the wave length of 460 /i^i. This is the maximum trans- 
mission of this solution. 
The other three curves shown in figure 5 were derived from the 
percentages of light transmitted by the alkaline alcoholic extracts from 
