I 



1902] THE STRUCTURE OF THE STARCH GRAIN 343 



present a starch cellulose. This latter term, according to Meyer, 

 has been used for a number of different substances : (i) mixtures 

 of amylodextrin and a-amylose ; (2) solutions of a-amylose and 

 /3-amylose ; (3) solutions of yS-amylose with various other sub- 

 stances, as nitrogen-holding substances, impure fatty products, 

 pure amylodextrin, and the walls of plant cells which are con- 

 tained in commercial starches unless carefully purified. He 

 obtained the a-am^-lose upon treating starch paste (Starkekleister) 

 with malt solutions (Malzauszug) and by the action of hot 

 dilute solutions of hydrochloric acid upon the whole starch 

 grain. The portion remaining (^-amylose) is distinguished 

 from the portion dissolved in that it is not soluble in water and 

 becomes slightly reddish, and not blue with iodine. 



One of the earliest views in regard to the development of the" 

 starch grain was that new layers were added to those previously 

 formed, these being separated from each other by layers of air 

 which were later called " Adhasionsflachen,'' *' Contactflachen," 

 and '*Grenzflachen" by Dippel (22), Strasburger (23),and Krabbe 

 (24) respectively. These terms, however, have been mostly 

 used by these authors in describing the structure of cell walls. 

 In 1858 Nageli (16) advanced the theory that the starch grain 

 consists of elementary particles, later termed by him ** micellae," 

 which he supposed to have the form of parallelopipedal prisms 

 with rectangular or rhomboid bases. Furthermore, according 

 to Nageli, these micellae possess a watery film, are embedded 

 in a mother liquor which differs from them in composition, 

 and are held together by certain forces. The growth of the 

 starch grain is effected by the interpolation of new material 

 among the particles already formed, this new substance being 

 utilized in part in increasing the size of the micellae already 

 formed, and also to form new micellae, which develop and 

 arrange themselves according to the laws which the micellae 

 previously formed have obeyed This theory is known as the 

 ''intersusception theory," while the earlier one is spoken of as 

 the ''apposition theory." In addition to these two views in 

 regard to the structure of the starch grain, Schimper (17) con- 

 sidered that it is made up of sphere-crystals which he called 



