684 



SCIENCE. 



[N. S. Vol. XVII. No. 435. 



and 160° C. for from four to ten minutes, 

 there will be a splitting or popping open of 

 the grain from the apex and a modification 

 of the contents varying according to the" 

 kind of corn. In the sweet corn the grain 

 swells very perceptibly, becoming hollow in 

 the center, the endosperm becoming more 

 or less friable and containing an increased 

 amount of reducing sugars. In the dent 

 corns there is a splitting of the hulls and 

 the endosperm, and this may take place on 

 the flat surface or along the edge, or the 

 upper portion may separate like a lid. 

 There is not much alteration in the endo- 

 sperm cells of this class, only a small 

 amount of soluble starch being formed. In 

 the pop-corns there is a splitting of the 

 grain along the two radii, the endosperm 

 swelling very considerably, the peripheral 

 portions cohering with the hull and thus 

 leaving a central more or less rounded 

 mass; where the popping is perfect the 

 quarters turn back and meet below the 

 embryo. On examining the endosperm of 

 the popped grain it is observed that there 

 has been considerable alteration in the 

 starch grains and cell walls, and that the 

 starch has been changed into a soluble 

 form, the amount of which depends upon 

 the degree of alteration in the endosperm 

 cells and their contents. 



The structural characteristics of the 

 starch grains in the altered areas of the 

 different pop-corns would seem to indi- 

 cate that the popping of the grain of corn 

 results from the expansion of the individual 

 starch grains, the degree of expansion de- 

 pending upon the relative amount of water 

 and air in the grains. As an illustration of 

 this it may be stated that perfectly fresh 

 pop-corn or pop-corn that has been soaked 

 in water for twenty-four hours will pop 

 but little in the true sense of the word. On 

 the other hand, a pop-corn which was seven 

 years old, 4)ut had not lost its germinating 

 power, would not pop unless first soaked in 



water and then allowed to dry for from 

 four to twelve hours. That this property 

 probably resides in the starch grain is fur- 

 ther shown by the fact that pieces of the 

 pop-corn grain will pop. 



Beaver County (Pa.) Orchids: Mr. Ira 



Franexin Mansfield, of Beaver, Pa. 



A brief account of twenty-eight species 

 of orchids which the writer has found in 

 Beaver County, Pa. 

 The Forward Movement in Plant Breeding: 



Professor L. H. Bailey, of Ithaca, N. Y. 



The current idea in plant breeding is to 

 breed 'varieties,' to produce something 

 'new' that can be named and described. 

 However, a variety is not a thing or an 

 entity, but only an aggregation of forms 

 that agree rather more than they differ. 

 Any one of these minor forms might be 

 separated as another variety. The ulti- 

 mate form or unit is the individual plant, 

 and from this individual, irrespective of 

 the variety it represents, the plant-breeding 

 of the future must proceed. 



The new idea is to breed for definite 

 characters that make for efficiency. We 

 must 'scale' our plants according to what 

 they perform or what they contain. Thus, 

 the new corn breeding does not attempt to 

 produce new 'varieties' of corn, but to in- 

 crease the efficiency of any variety by in- 

 creasing its yield, protein or starch con- 

 tent, its drought-resisting or disease-resist- 

 ing qualities. The new work with corn in 

 Illinois, with wheat in Minnesota, with cot- 

 ton and other crops by the United States 

 Department of Agriculture, was described 

 and illustrated. 



The first thing that strikes one in all this 

 work is its contrast with the old ideals. 

 The 'points' of the plants are those of 

 'performance' and 'efficiency.' It brings 

 into sharp relief the accustomed ideas as 

 to what are the good 'points' in any plant, 

 illustrating the fact that these points are 



