Nov., 1922] SPONSLER — STRUCTURE OF STARCH GRAIN 
491 
arrangement. The fact that both are formed at the contact surface of 
protoplasm favors the idea that the layers of atoms are parallel to the sur- 
face, whether curved or plane. 
In conclusion, two points seem to stand out as fairly definitely proved: 
(i) that there is, within limits, a regular and fairly uniform arrangement of 
atoms in the starch grain; and (2) that this regularity is destroyed by 
crushing the grain, which leads to the additional statement that the regu- 
larity is not that of crystalline structure. These statements oppose the 
spherocrystal theory of Schimper (30) and Meyer (3), while they favor the 
assumption made by Kabsch (23) in 1863 that the grains have a physical 
uniformity which, however, is not sufficiently regular to assign crystallo- 
graphic axes to them. Or it may be that, instead of planes such as are 
found in crystals, the regularity takes the form of curved layers. 
It is a pleasure to record here an indebtedness to Dr. George J. Pierce 
of the Department of Botany, and to Dr. David L. Webster and Dr. Frank 
C. Hoyt of the Department of Physics, for helpful assistance and suggestions. 
Stanford University 
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