STARCH-SUBSTANCE, AND THE STRUCTURE, ETC., OF THE STARCH-GRAIN. 41 



mation in chromatophores, but with marked subsequent growth (in many Cotylcdones) ; (3) 

 the formation at the surface of the chromatophores (Phaius). The first method of growtli 

 gives rise to a type of small, lamellated starch-grains; the second and third methods to types 

 of large lamellated grains. In the development of types of grains 1 and 2, the growth of 

 the grains takes place presumably by a chemical metamorphosis of the chromatophore- 

 substance, while in the growth of type 3 the role of the chromatophore is problematical. 



The so-called starch cellulose or skeletons prepared by C. Niigeli by subjecting starch 

 to the prolonged action of saliva, were obtained by Meyer (Botanische Zeit., 188G, xlix, 

 697, 713) by the agencies of dilute acids, pepsin, diastase, and saliva. Meyor found that 

 after digestion had proceeded sufficiently long the skeletons are colored yellowish or reddish- 

 brown with iodine, and that they consist of pure amylodextrin. This substance, he notes, 

 crystallizes very readily, usually in the form of spherical spherocrystals (rarely plate-like), 

 resembling starch-grains which have a concentric structure. These spherocrystals, he 

 states, behave similarly to starch-grains in polarized light, except that the dark cross is 

 not orthogonal but diagonal, a phenomenon which evidently is dependent, he states, 

 upon the orientation of the needle-crystals. The saliva-skeletons, as well as the acid- 

 skeletons, behave exactly like the starch-grains towards polarized light. The microchemical 

 similarity of the spherocrystals of amylodextrin and the saliva and acid skeletons proves, 

 he contends, the identity of the substance of the three structures. This statement he sup- 

 ported by the results of experiments with acids, alkali, and chloride of zinc and iodine, by 

 which it was found that all were affected in the same way. 



The starch cellulose or skeleton-like substance described by Nageli and others was 

 prepared by Griessmayer (Allgem. Bauer- u. Hopfenzeit, 1887, xxvi, 147) by subjecting 

 1000 grams of potato starch to the action of 6 liters of a 12 per cent hydrochloric acid for 

 100 days in the cold. From this preparation, after washing free of acid, sugar, etc., and 

 drying, a quantity of starch celhdose was obtained that weighed 300 grams. This sub- 

 stance was almost completely soluble in boiling water; and by freezing such a solution 

 amylodextrin crystallized out in the form of spherocrystals composed of minute radial 

 needles. Brown and Heron (Ann. d. Chem. u. Pharm. 1879, cxcix, 189) question whether 

 cellulose is an original constituent of the grain or an after-formation. 



The conception of the rod-like crystalline arrangement of the particles of the starch- 

 grain received further support in the investigations of Buscalioni (Botanische Jahresbe- 

 richte, 1891, xix, 489) with Zea starch. The seeds of corn, not quite ripe, were broken 

 up and boiled for 30 seconds in 1 c.c. of chloroform containing several drops of a solution 

 of chromic acid. The pieces of the seeds were spread out and examined under the micro- 

 scope, and numerous grains of starch swollen to various degrees were noted. In the slightly 

 swollen grains radial streaks were seen which passed from the center of the grain to the 

 periphery, and which were placed in two directions so as to cross each other at right angles, 

 thus giving the grain the appearance of being composed of numerous rhombic pieces 

 regularly arranged. In the more swollen grains the lines were replaced by small points 

 arrangetl concentrically and radially. If the action of the chromic acid goes on for a 

 longer time every trace of a definite structure vanishes and the whole grain appears to 

 be a hyaline mass. 



In a later article {ibid., 1899, xxvii, 282), Buscalioni found in the cortex of the root 

 of Juncus tenuis, especially within the endoderm, an accumulation of simple and com- 

 pound starch-grains. The grains which appear in cells poor in starch were sometimes 

 inclosed in a space of varying form and consistency, and in the nature of a dense mucus 

 substance, so as to constitute a capsule. These capsules lie in a corner of the cell or on the 

 cell-wall, while others are attached to the wall by a little stalk. Aggregations of grains 

 are sometimes inclosed in a common capsule. Capsules were also observed which did not 

 contain a trace of starch. Sometimes pectin, and also cellulose, were present. The author 



