ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 97 



Albuminoid Constituents of Plants.*— C. Schulze has determined 

 the existence, in seedlings of lupin, besides asparagin, of phenylamido- 

 propionic acid and amidovalerianic acid, and probably also of lucin 

 and tyrosin. In addition there occur also peptone, bodies of the 

 xanthin group — which must be regarded as products of decomposition 

 of the nucleus — and lecithin. Important constituents of seedlings of 

 the gourd are glutamin and tyrosin. The author has also investi- 

 gated the albuminoid constituents of beet-root, potato-tubers, and of 

 the young shoots of various trees. A specially interesting observation 

 is that the young shoots of Platanus orientalis, in addition to asparagin, 

 contain also not inconsiderable quantities of allantoin. In young 

 shoots of the plant are also bodies of the xanthin-group. 



Periodical Formation of Acids in Succulent Plants.f — H. de 

 Vries has investigated the cause of the well-known phenomenon that 

 in many plants the tissue has a strong acid reaction in the morning, 

 while in the evening only a slight trace of free acid remains. The 

 acid is chiefly malic acid, and the phenomenon is most strikingly 

 displayed in succulent plants belonging to the order Crassulacese ; the 

 largest quantity was observed in Echeveria metallica. The cause of 

 the periodicity is stated by De Vries to be the greater rapidity with 

 which the decomposition of vegetable acids takes place in the light 

 than in the dark, although this decomposition is progressing at all 

 times, by day and by night, in all plants ; while the production of 

 acid, although originating from the action of light on the leaves, 

 actually takes place only in the dark. The decomposition of these 

 acids he regards as a process of oxidation, accompanied by the pro- 

 duction of carbon dioxide and water. 



Production of Hydrocyanic Acid by Plants-t— A. Jorissen has 

 demonstrated the existence of the power of eliminating hydrocyanic 

 acid in a large number of plants belonging to widely separated natural 

 orders, and in different parts of the plant ; the list including one 

 fungus, Marasmiiis oreades. In addition, he has found the same 

 property of disengaging hydrocyanic acid and benzoin aldehyd in a 

 myriopod of the genus Fontai'ia when excifced.§ 



Presence of Amylase in Leaves. II — L. Brasse has detected 

 amylase as an invariable constituent of the leaves of plants. It was 

 never accompanied by microbes ; the starch was always transformed in 

 the ordinary way, giving rise to a reducing sugar mixed with dextrine. 



Autumnal Tints of Foliage.^ — H. C. Sorby points out that the 

 autumnal tints of foliage are due to chemical changes in the pigments, 

 consequent on a more or less complete loss of vitality. As a general 

 rule the colour of leaves in their normal condition depends on 

 variable mixture of two perfectly distinct green pigments and of 

 at least four perfectly distinct yellow substances. The first 



* Landwirthsch. Jahrb., xii. See Bot. Ztg., xlii. (1884) p. 364. 

 t Bot. Ztg., xlii. (1884) pp. 337-44. 353-8- 

 X Bull. Acad. R. Sci. Belg., liii. (1884) pp. 256-8. 

 § See this Journal, iii. (1883) p. 53. 

 11 Coinpte.9 Rendus, xcix. (1884) pp. 878-9. 

 ^ Nature, xxxi. (1885) pp. 105-6. 

 Ser. 2.— Vo-.. V. H 



