184 differentiation and specificity of starches. 



Polygonum Fagopyrxjm. 



The small grains of this plant were not easily observed. Under magnification of 300, 

 in the first stages of erosion the grains have a striped appearance, with fine, dark, dotted 

 lines radiating from the center to the periphery. Magnified 500 times, it can clearly be seen 

 that the change begins on the outside. Numerous narrow canals are found on the peri- 

 phery which penetrate into the center of the grain ; the canals appear lighter than the other 

 parts, due to the lamellas of the gi-ain, which do not show under a lower power. The sub- 

 stance in the center of the grains dissolves more easily, and the canals therefore run together 

 here into a small hollow, and the process of solution now continues centrifugally. Finally, 

 only a ring of isolated small grains is left which is evidently held together by the remaining 

 invisible mass of cellulose. 



Fagopyrum Esculentum. 



The same process takes place in the germinating seeds of buckwheat, but among all the 

 seeds examined those of buckwheat were most easily affected by the ferment. Only small 

 portions of the grains were left after 24 hours' action of the ferment treated with strong 

 formic acid, and in 48 hours no trace of the starch-grain was left. The minimum of the 

 time reaction is probably only a few hours. 



Triticum Sativum var. Vulgare. 



Baranetzky found that the starch-grains of wheat are almost as easily affected as 

 those of buckwheat. As is well known, there are two kinds of starch-grains in the seeds 

 of wheat, the large, flat, crescent-shaped and the small, more or less spherical. The erosion 

 process described is that of the large grains. The first changes are Uke those of Polygonum, 

 the same striped appearance, and the same radiating lines, but the latter not always ex- 

 tending to the center. Similar canals also run from the flat sides into the inner part of 

 the grain; on the surface of the grain these canals appear as small, clearly outlined circles, 

 greatly resembling the round tufts of the parenchymatous cells. In the meantime tlie 

 clear parts of the grain grow wider, so that the unchanged portions ha\'e the appearance 

 of dense radial bands in the clear, concentric-layered grain. At the same time the clear 

 portions begin to melt away from the outside, but the bands do not keep pace with tliem, 

 the ends of the latter usually protruding more or less freely. After these bands are finally 

 absorbed only a small disk remains, which is formed from the central part of the grain 

 where the lateral canals did not penetrate. This disk now dissolves at its upper surface 

 and at the walls of the canals which have penetrated from the sides of the grain into its 

 center. At last only an u-regular lump, riddled with holes, is left of the entire starch- 

 grain, and this also finally dissolves. Very often the process of solution begins with the 

 formation of concentric spaces which evidently correspond to the dissolved single groups 

 of lamella;. In such cases the grain usually dissolves from the outside, without previous 

 formation of canals. Usually the formation of the centric spaces combines in different 

 ways with the radial canals, producing varied and complicated appearances in the process 

 of erosion. In rare cases, starch-grains may be found which dissolve equallj^ in all parts. 

 They then become very transparent and show 2 to 3 concentric zones of varying density, 

 gradually merging into one another. The final disappearance of such grains takes place 

 either by a melting away from the outside or by a gradual complete solution. 



No cellulose skeleton was found in any of the starch-grains of Triticum after the granu- 

 lose had been extracted. Watery solutions of iodine always have a violet reaction, even 

 in those parts of the grains which were on the point of disappearing. This, Baranetzsky 

 states, need not necessarily mean that the grains of Triticum contain no cellulose, for the 

 same results should be obtained if the cellulose were more soluble, or at least equally as 

 soluble, as the granulose of the grains in question. 



