396 



Plant Physiology 



In the second case, reported by Hickman, to be con- 

 trasted with the preceding, " three grades were used : 

 first grade, the large grains ; second grade, the best of the 

 grains passing through the sieve in screening out the first 

 grade; third, unscreened wheat as it came from the 

 thresher." The experiments were continued nine years, 

 and after the first year, the selections for each were made 

 from the same grade of the previous year : - 



There is also difference of experience with respect to 

 large and small grains from the same head or plant. 



236. Experiments with cotton. - - Comparative pro- 

 duction tests of the value of heavy cotton seed over the 

 usual farm product have been made at the United States 

 Department of Agriculture. 1 The heavy seed were sepa- 

 rated, in the case of those varieties the seed of which are 

 covered with fuzz, by special devices and methods. The 

 field tests were made with results as shown in the table 

 on the next page. 



1 Webber, H. J., and Boy kin, E. B., " The Advantages of Planting 

 Heavy Cotton Seed." U. S. Dept. Agl., Farmers' Bui. 285 : 16 pp., 6 

 figs., 1907. 



