1913] SCHLEY—GEOTROPIC STIMULATION 487 
_ half an hour, so that the average stimulation was 45 minutes. 
After weighing, the two halves (upper and lower) were placed 
in 85 per cent alcohol heated to 70° C., and allowed to stand 
for two weeks. The material was then cut up fine and extracted 
48 hours in an extractor similar to the Soxlet extractor. The 
extract together with the alcohol used in preserving the material 
was evaporated to moist dryness over the steam bath and brought 
to constant weight in vacuo. The dried material was dissolved 
in water, ro cc. of concentrated hydrochloric acid and 20 cc. of 
chloroform added, and the whole made up to 1000 cc. in volume. 
The water-soluble portion was filtered from the chloroform-soluble 
or lipoid fraction and the sugar determination made upon it directly. 
The lipoid fraction was dissolved in alcohol, and made up to 500 cc. 
in volume; so cc. of each fraction was used in the determination. 
The fractions were hydrolized and the tannin precipitated before 
testing for sugar. The method of hydrolysis used was that 
described in Bulletin no. 107, p. 41, U.S. Dept. of Agric., Bur. of 
Chem. The tannin was precipitated after hydrolysis by means 
of lead acetate and sodium sulphate. The sugar was determined 
by the cuprous oxide method as described in the above mentioned 
bulletin (p. 242). The amount of cuprous oxide was determined 
by the volumetric potassium permanganate method (bid. pp. 52, 
53). An x/2o0 solution was used. The calculations were based 
on the mg. of copper oxidized in the change from cuprous to 
cupric oxide, and the invert sugar equivalent obtained from the 
accompanying table (p. 243). Table V shows the results obtained. 





TABLE V 
Percentage 
Flank Fresh wt. Dry wt. Amt. sugar er dry wt. 
Concave..... 231.635 II. 2004 2.7763 1.198 7 ak 
Convex ..... 242.275 11.8064 1.9202 0.792 ; 



These results differ from those of Kraus in point of time of 
stimulation. He found the sugar content on the convex side to 
increase during the period of one hour and then to decrease. e 
experiment given shows an increase of 0.406 per cent of the fresh 
