CONCLUSIONS RELATING TO THE STARCH-SUBSTANCE, ETC, 79 



phore; therefore the starch-grain will grow most rapidly where the layer of chromatophore 

 substance is greatest. As a consequence, the shape of the starch spherocrystal is dependent 

 upon the sliape assumed by the chromatojihore. 



Biitsclili (loc. cit.) also noted the correspondence of the structure of the starch-grain 

 and crystals of inulin, and he also prepared artificial starch-grains in the form of sphero- 

 crystals which had the crystalline properties of normal starch, and which had a lamellated 

 structure that bore a marked resemblance to the lamellse of the normal grain. The corre- 

 spondence between typical spherocrystals and starch-grains in regard to the peculiarities 

 of solution and reformation, and to the mechanism of the formation of layers of varying 

 density may also be found in the studies of Hansen (Arbeit, d. Botan. Instituts in Wurz- 

 burg, 1884, in, 110), Rodenwald and Kattein (Zeitschr. f. physikal. Chem., 1900, xxxiii, 

 579), and Ostwald (Lelirb. d. allegem. Chem., 1891, i, 1041). 



Various statements or claims in relation to Biitschli's honey-comb theory, Niigeli's 

 micellar theory, and Meyer's trichite theory were strongly attacked by Fischer (Beit. z. 

 biol. d. Pflanzen, 1898, i, 53; Beihefte z. bot. Centralbl., 1902, xii, 22G), who showed in all 

 instances that most of the claims of what these theories or hypotheses explain are incon- 

 sistent with facts. Neither Biitschli's nor Meyer's theory, Fischer states, is compatible with 

 the physical properties of inulin crystals, wliich, as has been shown, are essentially like the 

 starch spherocrystals. Fischer regards Niigeli's hypothesis as being well-conceived and sys- 

 tematically elaborated, but based upon fanciful invention and unsupported by facts, and 

 he states that Nageli, without producing proof, advances the theory that the crystals, or 

 micellie, and their imbibed water are disposed in distinct layers and held together by some 

 mysterious force. Fischer compares the particles of water-free starch with other crystals, 

 lime-spar for instance, in respect to their properties of cohesion and refraction, and he goes 

 on to show that the presence of water in the starch-grain is not a physical phenomenon, or 

 one of capillarity, but one of chemical affinity. In regard to Niigeli's hypothesis of growth 

 by intussusception, Fischer states that to accept it we must admit the existence of quite 

 a number of special properties which are inconsistent with our knowledge. 



Fischer looks upon Meyer's trichite theory, in the explanation of the cause of the 

 lamellation of the starch-grain, as being untenable, and he disproves Meyer's statement of 

 the influences of alternation of light and darkness, and of the changes in concentration of 

 the mother-liquor, on the formation of the lamella?. Cuttings exactly like those described by 

 Meyer were kei)t in the dark for two weeks and then in the condensed light of an incandescent 

 lamp for one week. In one of four experiments stratified starch-grains like those described 

 by Meyer as being caused by the alternating influences of light and darkness were observed. 

 Fischer notes the fact that results confirmatory of his own of the negative effect of light on 

 lamellation were recorded by Salter by treating leaves of Pellionia with sugar solutions. (See 

 also St. Jentys, page 58.) Fischer's article is quite long and full of detail. 



COXCU'SIOXS RELATING TO THE STARCH-SUBSTANCE AND THE STRUCTURE AND MECHANISM OF 



FORMATION OF THE STARCH-GRAIN, BASED CHIEFLY UPON THE FOREGOING LITERATURE 



AND IN PART UPON OBSERVATIONS RECORDED IN SUBSEQUENT CHAFFERS. 



(1) The starch-substance is not a unit body, but exists in a number of stereoisomeric 

 forms. It probably differs specifically in the grains of different plants, in the grains of 

 the same plant, and in the individual grains, and is indicated by differences in the 

 behavior towards iodine, aniline dyes, and various other agents. In any given mature 

 grain it may be found that certain parts behave differently from other parts to reagents, 

 indicating, for instance, not only specific differences in the nature of the starch-substance 

 of the capsular or outer layer and the inclosed part, but also of the chfferent lamellse 

 and even in different parts of a given lamella. The different lamellse vary in density 

 and solubility, increasing in density and decreasing in solubility from witliin outward, 



