Jan., I92i] WIGGANS — OSMOTIC CONCENTRATIONS OF GUARD CELLS 35 
Figure 3 shows the results of observations on cyclamen made on January 
I and January 2, 1918, at Columbia, Missouri. Here a new but entirely 
similar series of concentrations of CaCU was used. The results recorded 
Fig. 2. Cyclamen. Observations made at Ithaca. 
here were secured after several days of preliminary work with the new 
plants, apparatus, and solutions in order to make the error as small as 
possible. 
It is quickly seen that these results are very different from those secured 
at Ithaca. There is a rise in osmotic pressure in the morning and a fall in 
(PA/w. ' gA.A\. /O/v/w. /Ins. ;iF./vx, Qffftn. 
Fig. 3. Cyclamen. Observations made at Columbia, Mo. 
