ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
303 
Phytoptideae on Geranium sangnineum, G. dissedum, species of Bromus , 
and Galium Mollugo , The changes which take place in the nucleus 
are especially striking. It is frequently increased enormously in size ; 
and, in addition to the normal nucleole, contains a number of accessory 
or pseudo-nucleoles. In many of the cells attacked there are also bodies 
having the appearance of secondary nuclei. The nucleus frequently 
divides by simple constriction, without mitosis, or by a process of 
budding. 
(2) Other dell- Contents (including 1 Secretions). 
Oil in Leaves.* — According to researches made by Herr S. Rywosck 
on deciduous and evergreen flowering plants, Muscineae, and Algae, the oil 
contained in leaves (or other green organs) has an entirely different 
function from the oil contained in the stem, and cannot be regarded as 
a reserve food-material. Instead of being stored up in the winter and 
disappearing when the period of vegetative activity recommences, it 
remains, and even increases in amount, during the spring and summer, 
being very large even when the leaves have turned yellow in autumn. 
Its purpose appears to be to take up the xantliophyli. The diameter of 
the oil-drops usually varies between 5 and 18 /x, and there are most 
commonly several in a cell. The chemical nature of the oil, whether it 
belongs to the fatty or to the essential series, was not determined. 
Volatile Reducing Substance in Green Cells.*)* — Herren T. Curtins 
and J. Reinke discuss the nature of the volatile reducing substance 
which is the first product of assimilation in green cells, and which they 
decide to be of the nature of an aldehyd. They propose for it the 
formula C 7 H u O.CHO, or occasionally C 7 H 9 O.CHO. Further details are 
given with regard to its chemical and physical properties. 
Tannins in Fruits, f — From experiments made chiefly on the fruit of 
Biospyros, M. C. Gerber concludes that one object of the presence of 
tannins in fruits is to prevent the formation of pectic substances, and 
hence the fermentation of their saccharine contents. The tannins finally 
disappear by oxidation, without giving rise to carbohydrates. 
Production of Hydrocyanic Acid in the Pome8e.§ — M. L. Lutz states 
that amygdalin and emulsin are present in the seeds of plants belonging 
to the genera Malus, Cydonia, and Sorbus, but not in those of Pyrus , 
Mespilus , and Cratsegus. In the Pomeae emulsin was found in the paren- 
chymatous cells of the cotyledons, especially in the neighbourhood of 
the vascular bundles, but not in the palisade-cells ; none was found in 
the hypocotyl, plumule, or radicle. Amygdalin occurs in the cells of 
the cotyledons which contain emulsin, trituration giving rise to the 
odour of bitter almonds ; it is also present in the hypocotyl, plumule, 
and radicle. 
(3) Structure of Tissues. 
Leptome of Angiosperms.]! — Herr F. Czapek describes the highly 
differentiated leptome of Angiosperms as consisting of three distinct 
physiologico-anatomical tissue-systems, viz. : — (1) The transport system, 
* Ber. Deutscli. Bot. Gesell., xv. (1S97) pp. 195-200. f Tom. cit., pp. 201-10. 
X Comptes Rendus, cxxiv. (1897) pp. 1100-8. 
§ Bull. Soc. Bot. France, xliv. (1897) pp. 26-82. 
|| Ber. Deutscli. Bot. Gesell., xv. (1897) pp. 124-31. 
