788 
* 
Journal of Agricultural Research voi. xxvn, no. io 
sugars and the reducing sugars, but in 1919 the nonreducing sugars were 
estimated as sucrose. In the experiments of 1917 and in the case of corn 
in 1919, determinations were made of starch according to the official 
method of direct acid hydrolysis. In this method, however, the material 
estimated as starch includes the pentosans and other insoluble carbohy¬ 
drate bodies which undergo hydrolysis and conversion into reducing sugars 
on boiling with hydrochloric acid. The results, while not indicating the 
actual amount of starch, do show the increase or decrease of the complex 
carbohydrates in the leaves during a 24-hour period. 
DISCUSSION OF EXPERIMENTAL DATA 
Three comparative experiments were conducted with Dwarf Yellow 
milo and Pride of Saline com and one with Dwarf Yellow milo and Red 
Amber sorgo. In one experiment in 1917 Dwarf Yellow milo alone was 
under observation, while in 1919 in one experiment Pride of Saline corn 
was the only plant studied. During the three years, observations were 
thus made upon 10 different sets of plants. The two kinds of plants used 
in each of the comparative experiments were of th£ same age and were 
grown in alternate rows under the same cultural conditions, so that any 
differences that are observed in the changes of carbohydrates can be 
attributed to the specific differences of the plants under consideration. 
A general description of the plants at the time the material was collected 
is given in Table III. The evaporating power of the air during the time 
the plants were under observation was measured by Livingston porous 
cup atmometers, and the evaporation for each two-hour period during 
the time of each experiment is given in Table II. 
Table II .—Evaporation (in cubic centimeters) for the different periods of leaf sampling 
in 1916 and 1917, at Garden City , Kans., and in 1919, at Manhattan , Kans. 
