ZOOLOGY AND BOTANY, MICROSCOPYj ETC. 425 



Formation of Albuminoids in Plants.*— The following experiment, 

 performed by Herr C. O. Miiller, sbows the conditions under wbich 

 asparagin is formed in plants. If a portion of a plant is placed in dark- 

 ness by enveloping it in black paper, while it still remains connected 

 with the parent, and the older portions are left undisturbed, then an 

 accumulation of asparagin is formed, which, wben the light is admitted, 

 is absorbed. This does not occur in the fully grown parts save excep- 

 tionally. This result seems to show that the formation of asparagin is 

 independent of carbohydrates, and also that the amide formed is not a bye- 

 product of the interchange of matter within the plant. It has also been 

 found that even when a plant is growing under abnormal conditions when 

 all carbon dioxide has been removed from the air, asparagin is formed in 

 the young parts, but not in the matured portions. Consequently it appears 

 as if ligbt played as inconspicuous a part in tbe formation of asparagin 

 as carbohydrates. The author considers that asparagin is formed by the 

 union of inorganic nitrogen compounds and malic acid within the plant, 

 the acid being derived from the carbohydrates. 



Poulsen's Crystals.f — Sig. P. Calabrb has investigated the occurrence 

 of these crystals in Eryihrina mitrsefolia. He finds them almost entirely 

 absent from the root, most abundant in the stem. In the leaves there 

 are fewer in the lamina than in the petiole. In the floral region they are 

 few and very small. As to their constitution, the crystals consist for the 

 greater part of pure cellulose, which, towards the base, has undergone 

 a certain amount of lignification. The mineral constituent is calcium 

 oxalate. 



New nitrogenous constituent of the Lupin. | — Herren E. Schulze and 

 E. Steiger obtain, from an aqueous extract of the cotyledons of etiolated 

 seedlings of lupin, by the addition of tannic acid and sugar of lead, 

 acidulating with sulphuric acid, and decomposing by phosphoric-tungstic 

 acid, a basic substance to which they give the name arginine. The nitrate 

 presents the formula CgH^^N^OaHNOa + I^H^O. 



Production of Chlorophyll in an objective spectrum.§ — By means of 

 a normal objective solar spectrum, Herr J. Reinke found that the produc- 

 tion of chlorophyll took place most rapidly on both sides of the line C, 

 nearly in the interval A = 635 to A = 675 ; the curve falls from this 

 maximum towards both ends of the visible spectrum. Positive heliotropism 

 of seedlings is manifested even in the yellow when the light is sufficiently 

 strong. 



(3) Secretions. 



Chemical composition of certain Nectars. || — M. de Planta has made 

 a complete chemical analysis of a certain number of nectars. The 

 following is a 7-esume of the results. In the fresh nectar of Bignonia 

 radicans the author found 14 • 84 per cent, of glucose and • 43 per cent, of 

 cane sugar; in the nectar evaporated to dryness, 97 "0 per cent, of glucose 

 and 2 "85 per cent, of cane sugar. In the fresh nectar of Protea melUfera 

 17' 06 per cent, of glucose was found, but no cane sugar ; in the dry nectar 



* Landw. Versuchs-Stat., 1886. pp. 326-35. See Journ. Chem. Soc. Lond., 1887, 

 Abstr., p. 70. 



t Malpighia, i. (1886) pp. 169-75 (1 pi.). 



J Ber. Deutsch. Chem. Gesell., xix. (1886). See Bot. Ceutralbl., xxix. (1887) p. 167. 



I Ber. Deutsch. Bot. Gesell., iv. (1886) Gen.-Versamml., p. cxix. 



II Zeitschr. f. Physiol. Chem., x. p. 3. See Bull. Soc. Bot. France, viii. (1886) Rev. 

 Bibl., p. 212. 



1887. 2 F 



