ALEUR ONE- GR A INS. 



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coagulated albumen ; but it may be a yet unknown proteid. With aleurone-grains 

 containing crystalloids, after careful solution, a similar membrane remains, but the 

 crystalloid itself also leaves behind one of the same kind ; this occurs also in the 

 solution of globoids in acetic or hydrochloric acid, and reminds one of the similar 

 behaviour of true crystals of calcium oxalate. 



The crystaUine enclosures of calcium oxalate occur as clusters, distinct crystals, 

 and needles, but are not commonly met with. 

 The globoids, on the other hand, are never absent 

 lom aleurone-grains; when they are accom- 

 panied by crystals, it is almost always the case 

 that the grains of one cell contain only globoids, 

 those of another only crystals, as in Silyhum 

 marianuvi, and all Umbelliferse that have been 

 examined. There occur however exceptions ; 

 in the grape-vine a globoid forms itself round 

 a crystal or a cjuster of crystals. The globoids 

 are soluble in all inorganic acids, and in acetic.- 

 oxalic, and tartaric acid, but not in dilute 

 potash. 



The globoids, like the crystals, may occur 

 in an aleurone-grain singly or many together; 

 in the latter case they are small, and even too 

 minute to be measured, but are then present 

 in enormous numbers in one grain, e.g. Lu- 

 pinus luteus, L. polyphyllus, Delphinium Requienii, &c. Large globoids surrounding 

 crystals occur singly, the largest in the grape-vine. Pfeffer found crystals accom- 

 panying crystalloids only in jEthusa Cynapium. The enclosed substances are usually 

 absent from very small aleurone-grains. 



In some seeds there is' in each cell one aleurone-grain distinguished from the 

 others by its size (' Solitar ' of Hartig), both when crystalloids are present and 

 when they are absent {Elaeis, Myristica, Vitis, Lupinus luteus)\ it may be dis- 

 tinguished by its enclosed substances. Thus in Lupifiiis luteus it contains a tabular 

 rystalloid ; the other surrounding grains only small and numerous globoids. In 

 nlybum a cluster of crystals lies in one large grain, in the others a number of 

 keedle-shaped crystals. In other cases the enclosed substances are similar, as is 

 le case with the globoids, which are merely larger in the large grain. 



The crystalloids are tolerably widely distributed in aleurone-grains, although 

 le greater number of seeds are destitute of them. They are not, however, cha- 

 icteristic of natural families, but may be present or absent in members of the 

 ime family; thus among palms, Sabal Adansonii is without, Elaeis guineensis has 

 rystalloids ; in the same manner all Umbelliferae which have been investigated want 

 ^hem except ^thusa Cynapium. In other cases all seeds of the same family appear 

 contain crystalloids, as in the Euphorbiacese, among which Ricinus supplied the 

 rst example of fine crystalloids in the aleurone-grains. 



The matrix which surrounds the grains of aleurone in oily seeds is, as has 

 Jen mentioned, always a mixture of oily matter and proteids, but the proportion 



Fig. 48. — Cells from the emlosperm of Ricinns 

 commtcnis (X 800). A fresh, in undiluted glycerin,^ in 

 dilute glycerin, C warmed in glycerin, D after treat- 

 ment with an alcoholic solution of iodine, the aleu- 

 rone-grains are destroyed by sulphuric acid, the 

 proteid remaining behind as a net-worlc. In the 

 aleurone-grains the globoid may be recognised, and 

 in (B, C] the crystalloid. 



