188 differentiation and specificity of starches. 



Zea Mays. 



As in the above, canals also form on the flat sides of the grain, which communicate with 

 those coming from the margin of Zea mays grains, and like barley and wheat starch grains, 

 the grains are ruptured by these ninnerous canals, which finally cause the complete dissolu- 

 tion of the grain. This is true not only of Graminacea: but also of a large number of other 

 plant orders. In Polygonum fagopyrum, Rheum rhaponticum, Polygonum bistorta, Convolvulus 

 (root), Adoxa moschatelUna (rhizomes), Galanthus nivalis (scales of bulbs). Narcissus poeii- 

 cus, Tulipa, and Gcsneriana (scales of bulbs), the tlissolution of the starch-grain by pore- 

 canals may be observed. 



Hyacinthus Orientalis. 



The distinguishing characteristic of erosion in these starch-grains seems to be that the 

 formation of pore-canals may be combined in various ways with the development of inner 

 cavities, each grain thus presenting a different picture. While some grains are eroded by 

 numerous ramified passages, almost equal in uidth, others show merely distinctly outlined 

 cavities of various shapes which naturally have an opening for the ferment at any indifferent 

 part of the surface of the grain. These grains are a striking example of the fact that the 

 diastatic ferment during its action on the starch-grain does not penetrate the starch-sub- 

 stance. The skeleton remaining after the action of the ferment, as well as the tiny broken 

 particles resulting from the breaking up of the grain, show all the characteristics of normal 

 starch-substances. 



Phaseolus Multiflorus. 



In these grains also the diastatic ferment enters the grain from without, and the 

 solution of the starch-substance takes place from within after the ferment has passed through 

 these canals into the inner part of the grain. Before germination has begun, the large 

 grains of the cotyledons of Phaseolus have a distinct inner cavity, formed by the basal 

 parts of radial fissures. These fissures differ from ferment passages in that they usually 

 end in a sharp point on the margin of the grain, while the latter, as a rule, have a rounded 

 apex. Wlien the fissures begin to widen and their ends become round we know that the 

 ferment has penetrated the inner part of the grain. They perform as ferment passages 

 the same function in the erosion process as soon as conmiunication has been established 

 between the two. In grains with numerous fissures, the process of erosion may at once 

 appear to be determined by them, inasmuch as they take up the ferment from outside 

 and conduct it in definite passages. This is the case with Phaseolus multiflorus. Wlien 

 this has reached the inner cavity it naturally spreads, and as the hole enlarges dissolution 

 must take place from within. Starch-grains in which erosion takes place from the out- 

 side are usually comparatively large, with an eccentric hilum and distinct lamellae, the 

 latter less numerous at the hilum than at the latter end. The watery lamella) at this part 

 of the grain usually end blindly at the sides, wedging themselves in between the more 

 dense lamella;, usually at some distance from the outer surface, and never known to have 

 free ends. 



LiLiuM Candidum. 



The ferment attacks the entire outer surface of the grain with equal intensity, not affect- 

 ing the broad, densely lamellated end more than the hilum end. As soon as ferment action 

 begins, the lateral increase of the outer lamellae must cease, and we then have starch-grains 

 with more or less substantial lamelhe and free ends, according to the intensity of the diastatic 

 action. The sides of these grains exhibit the same characteristics of erosion as those described 

 in Graminacea, the ferment coming from the peri])hery and acting more energetically on the 

 watery layers than on the dense ones, jn'oducing similar bands and protuberances. 



In germinating seed of Lilium candidum, Phaius, Lathraa, and Orobanche not all of 

 the gi-ains dissolve from the outside. In many grains the margin remains intact until 



