240 SUMMARY OF CURRENT RESEARCHES RELATING TO 



aleurone-grains liave been proved to be vacuoles containing albuminoid 

 substances whicb have undergone desiccation. He proposes to limit in 

 future the use of the term vacuole to actual cavities in the protoplasm, 

 and to call the structures hitherto termed vacuoles which make up the 

 cell-sap Jiydroleucites, corresponding to amyloleucites, chromoleucites, 

 chloroleucites, elaioleucites, oxalileucites, &c. These hydroleucites may 

 be tanniferous, oxaliferous, coloured, albuminiferous, &c., the last cor- 

 responding to the structures ordinarily known as aleurone-grains. They 

 have been rendered for the time passive and inert by desiccation, and 

 pass again into the active state during the germination of the seed. 

 They may be distinguished as passive or reserve-leucites in contra- 

 distinction to the active leucites. 



Xanthophyllidrine.* — Prof. L. Macchiati gives a short note on this 

 substance, which he believes to be entirely new and quite distinct 

 from xanthophyll, or from the yellow colouring matter of petals, being 

 especially distinguished by its property of crystallizing, and by its 

 insolubility in ether and alcohol. It is an invariable accompaniment 

 of chlorophyll, at least in all flowering plants examined, and probably 

 exercises an important function in connection with it, which will be 

 the subjects of future investigation. 



New Principle from Ergot of Rye, Ergosterin.f — M. C. Tauret 

 describes the preparation, composition, and chemical and physical 

 properties of ergosterin, a new crystallizable substance obtained from 

 ergot of rye. Ergosterin gives the same colour reactions as chole- 

 sterin, except in the case of sulphuric acid and chloroform. 



Colouring Matter of Drosera "WMttakeri.J— Prof. E. H. Eennie 

 has examined the tubers which grow at the end of the underground 

 stem of this species, found in the neighbourhood of Adelaide, and 

 finds them to contain a red colouring matter with the formula 

 CjiHgOi, probably a methyl-trihydroxy-napthaquinone. 



Mineral Substances in Leaves.§ — Sig. G. Briosi has examined the 

 amount of ash in the leaves of a large number of trees and shrubs, 

 both evergreen and deciduous, belonging to a great variety of natural 

 orders, and gives the following as his general conclusions. 



Except in a few cases, the amount of mineral substances in ever- 

 green leaves increases vfith age, while the proportion of organic sub-, 

 stances not only does not increase, but even tends to diminish. The 

 proportion of mineral substance is less in the petiole than in the 

 lamina ; and in the petiole the amount both of mineral and of organic 

 substances increases with age. In Eucalyptus globulus the horizontal 

 are richer in mineral matter than the vertical leaves. 



In trees with deciduous leaves the quantity of inorganic substances 

 increases, during the first months of life, from spring to autumn (except 

 in Cerasus avium); in the annual leaves of herbaceous plants the 

 quantity of ash does not increase with age, but decreases regularly from 

 spring to autumn. In the wood and bark the proportion of inorganic 



* Nuov. Giorn. Bot. Ital., xx. (1888) pp. 474-6. 

 t Comptes Eendus, cviii. (1889) pp. 98-100. 

 t Trans. Koy. Soc. S. Australia, x. (1888) pp. 72-3. 



§ 1st. Bot. R. Univ. Pavia, 1888, 63 pp. See Bull, Soc. Bot. France, xxxv. 

 (18S8), Rev. Bibl., p. 177. 



