342 BOTANICAL GAZETTE [novembek 



and thus substantiated the view of Fritsche concerning its devel- 

 opment. 



If we consult any of the standard works on organic chem- 

 istry, we find that the formula which is generally accepted for 

 starch is n {Q^ H^^^ O^), this being the formula recognized by 

 Pfeffer, Tollens, and Mylius. It is supposed that the molecular 

 composition is quite complex, the grain being composed of 

 different single groups of Cg H^^j O5 or multiples of the same. 

 While this formula may be accepted in a general way, still it has 

 been shown that there are at least two substances which enter 

 into the composition of the starch grain. Nageli (16) has 

 shown that the starch grain consists of two different substance*=, 

 one which is soluble in ferments, and called by him granulose, 

 and another which is insoluble in saliva, and called by him starch 

 cellulose. He showed that when the starch grain was deprived 

 of its water the lamellae were not apparent, and therefore he 

 concluded that the layering was due to a difference in the 

 amount of water present in the different lamellae. This view 

 has given rise to the formula suggested by W. Nageli (18) for 

 the starch grain, which is 6Cg H ^ ^^ O^ -j-Hg O, or C3 ^ Hg g O3 i- 

 Maschke (25) considered that the starch grain consisted of 

 alternate layers of cellulose between which starch substance was 

 deposited in two modifications, one soluble in water forming the 

 light-colored lamellae, and another insoluble in water forming 

 the dark layers. This view was not adopted, however, and 

 Nageli's theory prevailed until 1886, when Arthur Meyer (19) 

 demonstrated that the substance termed cellulose by Nageli, and 

 which was termed '* farinose" by Von Mohl (20), gave reactions 

 similar to artificially prepared crystals of amylodextrin. In 

 1895 Meyer (21) further considered the composition of the 

 starch grain and stated that it is made up of (i) a-amylose, (2) 

 ^-amylose, and (3) amylodextrin, a decomposition product of 

 amylose. He also expressed the opinion that inasmuch as there 

 is an anhydride of dextrose which does not readily take up water, 

 there is probably also an anhydride of amylose which even on 

 boiling with water is hydrated with difficulty, and that this is 

 the substance that has sriven rise to the belief that there is 



